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Title: Bromoil printing and bromoil transfer
Author: Mayer, Dr. Emil
Language: English
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BROMOIL PRINTING
AND
BROMOIL TRANSFER
BY
DR. EMIL MAYER
PRESIDENT OF THE VIENNA CLUB OF AMATEUR PHOTOGRAPHERS
_AUTHORIZED TRANSLATION
FROM THE SEVENTH GERMAN EDITION_
BY
FRANK ROY FRAPRIE, S.M., F.R.P.S.
EDITOR OF AMERICAN PHOTOGRAPHY
[Illustration]
AMERICAN PHOTOGRAPHIC PUBLISHING CO.,
BOSTON 17, MASSACHUSETTS
1923
COPYRIGHT, 1923
BY AMERICAN PHOTOGRAPHIC PUBLISHING CO.
_Manufactured in the United States of America_
_Electrotyped and printed, March, 1923_
THE PLIMPTON PRESS
NORWOOD·MASS·U·S·A
PREFACE
The bromoil process has always been one in which it has seemed difficult
to attain success. Though many books and articles on the subject have
been published, every writer seems to give different directions and
every experimenter to have difficulty in following them. The consequence
is that almost every successful experimenter with this process has
developed methods of his own and has frequently been unable to impart
them to others. One reason for this has been that each make of bromide
paper varies in its characteristics from the others and that methods,
which are successful with one, do not always succeed with another.
Various bleaching solutions have been described, and, as the bleaching
solution has two functions—bleaching and tanning, which progress with
different speeds at different temperatures—a lack of attention on this
point has doubtless been a frequent cause of unsuccess. Little attention
has also been paid to the necessity for observing the temperature of the
water used for soaking the print. The author of the present book has
investigated these various points very carefully, and for the first time,
perhaps, has brought to the attention of the photographic reader the need
for an accurate knowledge of the effect of these different variables.
In the following book he describes only a single method of work, without
variations until the process is learned, though he does describe various
methods of work which may be used to vary results by the experienced
worker. His method of instruction is logical and based on accepted
educational principles. He describes one step at a time fully and
carefully, explains the reasons for adopting it, and then proceeds to
the next step in like manner. We feel sure that every reader, who will
be reasonably careful in his methods of work and will follow these
instructions literally, will learn how to make a good bromoil print.
After attaining success in this way, the variations may be tried, if
desired.
While the author gives instructions for testing out papers to see if they
are suitable, it may be advisable to record here the results of some
American and English workers. H. G. Cleveland in AMERICAN PHOTOGRAPHY
for February, 1923, recommends, in addition to the papers specially
marked by their makers as bromoil grades, the following: Eastman Portrait
Bromide; P. M. C., Nos. 7 and 8; and Wellington, Cream Crayon Smooth,
Rough, or Extra Rough. He suggests that a rough test may be made of a
new brand of paper by placing a small test strip in water at 120° to
140° Fahrenheit for a few minutes and then scraping the emulsion surface
with a knife blade. If the coating is entirely soft and jelly-like, it
will probably be suitable for the process. If it is tough and leathery,
it will be unsuitable, and, if a portion of the coating is soft but the
other portion tough, then it will also be unsuitable. His experience is
that Wellington Bromoil paper is entirely suitable for the process. Chris
J. Symes in _The British Journal of Photography_ for December 1, 1922,
recommends for bromoil the following English papers: Kodak Royal, white
and toned; Vitegas, specially prepared for bromoil; Barnet Cream Crayon
Natural Surface, Rough Ordinary and Tiger Tongue. For transfer, he has
found the following suitable: Kodak Royal, white and toned; Kodak Velvet;
Barnet Smooth Ordinary; and Barnet Semi-matt Card.
The reader who is interested in bromoil transfer, will find the
directions of Mr. Guttmann on this process slightly different from
those of Dr. Mayer in minor points, but the worker who is far enough
advanced to essay this difficult process will be able to recognize these
discrepancies and choose the process which seems more useful to himself.
Metal etcher’s presses for transfer are sold at comparatively high prices
in the United States, but second hand ones may often be found in the
larger cities. Small wooden mangles with maple rolls may be had at fairly
low prices from dealers in laundry supplies, and have been found to be
useful.
Following the style of the German original, italics have been freely used
for the purpose of calling attention to the most important stages of the
process, rather than for the ordinary purposes of emphasis.
Grateful acknowledgment is made to Mr. E. J. Wall for assistance in the
first draft of the translation, and also in revision of the proofs.
FRANK ROY FRAPRIE.
BOSTON, February, 1923.
CONTENTS
PAGE
PREFACE iii
CONTENTS vi
PRELIMINARY REMARKS 1
CHAPTER I
PRODUCTION OF THE BROMIDE PRINT—Definition of Perfect Print—The
Choice of the Paper—Development—Control of the Silver Bromide
Print—Fixation 10
CHAPTER II
THE REMOVAL OF THE SILVER IMAGE—Bleaching—The Intermediate
Drying 29
CHAPTER III
THE INKING-UP—The Production of the Differential Swelling—The
Properties of the Relief and Its Influence on the
Character of the Picture—Effect of Warm Water—Effect of
Ammonia—The Utensils—Brushes—The Inks—The Support—Removal
of the Water from the Surface of the Print—The Brush
Work—Use of Dissolved Inks—Use of Rollers—Resoaking of the
Print during the Working-up—Removal of the Ink from the
Surface—Failures—Alteration of the Character of the Picture
by the Inking—The Structure of the Ink—Different Methods of
Working—Hard Ink Technique (Coarse-grain Prints)—Soft Ink
Technique—Sketch Technique—Large Heads—Oil Painting Style—Night
Pictures—Prints with White Margins—The Swelled-grain
Image—Mixing the Inks—Polychrome Bromoils 38
CHAPTER IV
AFTER-TREATMENT OF THE FINISHED PRINT—Defatting the Ink
Film—Retouching the Print—Refatting of the Print—Application of
Ink to Dry Prints 104
CHAPTER V
TRANSFER METHODS—Simple Transfer—Combination Transfer with One
Print-plate—Shadow Print—High Light Print—Combination Transfer
from Two Prints 115
CHAPTER VI
OIL VS. BROMOIL 134
CHAPTER VII
BROMOIL TRANSFER, by Eugen Guttmann—The Bromoil Print—The
Choice of the Paper—The Machine—Printing—Combination Printing
with One Bromoil—The Value of Combination Printing—Retouching
and Working-Up—Drying 142
CHAPTER VIII
THE PREPARATION OF BROMOIL INKS, by Eugen Guttmann—The
Varnish—Powder—Colors—Tools—Practice of Ink Grinding—Ink
Mixing—Permanency—Ink Grinding Machines 176
BROMOIL PRINTING AND BROMOIL TRANSFER
PRELIMINARY REMARKS
We all know what great progress photography has made in the last few
years. The most obvious sign of this advance is the fact that it has
gradually escaped from the practice of literal reproduction of the
objects seen by the lens, and slowly attained to the rank of a recognized
means of artistic expression, so that it can justly be considered as
a new branch which has grown out of the old tree of reproductive art.
This pleasing development may primarily be ascribed to the fact that the
practice of photography, which was originally confined almost exclusively
to professional workers, has gradually spread and has become a means of
recreation to the multitude in their leisure hours. It was the amateur
who demanded new methods and apparatus and thus gave a new impulse
to photographic manufacturing. Improvements of the most fundamental
character were made in optical apparatus, in the construction of cameras
of the most varied types, and in the fabrication of plates and films.
An extraordinary number of novelties has appeared in these lines in the
course of time; modern photographic apparatus makes possible the solution
of problems which would not have been attempted a few years ago, and
improvements are still appearing.
The situation in the matter of printing processes is quite different. We
are provided with apparatus and sensitive material for the production
of the photographic negative, in a perfection which leaves nothing to
be desired. To produce a print from the negative, however, we had until
recently no positive processes which were not well-known to previous
generations. This may be confirmed by a glance at any photographic
textbook written around 1880. The various printing processes, platinum,
bromide, carbon, and gum, which were until recently the alpha and
omega of printing technique, had been known for decades. Compared with
the methods for the production of negatives, printing methods showed
practically no advance; they remained in complete stagnation. We can
scarcely consider as an exception certain new methods brought forward
in recent years, which proved unsuccessful and quickly disappeared from
practice.
These facts can only be explained by remembering that the positive
processes, which were available to photographers and with which they had
to be satisfied, were rather numerous and offered a considerable variety
of effects. Nevertheless, a single characteristic was common to all
previously known photographic printing processes—their inflexibility.
Each of these processes, in spite of its individual peculiarities,
could do nothing more than exactly reproduce the negative which was to
be printed. It was possible to produce certain modifications of the
negative image as a whole, by printing it darker or lighter, or by using
a harder or softer working process. Changes on the negative itself for
the purpose of giving a more artistic rendering must, however, always be
very carefully thought out in advance and effected by retouching, often
difficult and not within the power of every photographer, or by other
methods which change the negative itself. If such modifications of the
negative proved unsuccessful, it was irreparably lost; if they succeeded,
the plate, as a rule, could no longer be used in any different manner.
The possibility of undertaking radical changes which might realize the
artistic intentions of the worker on the print itself, in order to save
the negative, and especially of planning and carrying out the deviations
from the original negative, which expressed the worker’s artistic
feelings, during the printing, was not afforded by any previously known
printing methods. A single exception was found in gum printing, if the
production of the image was divided into a series of partial printings.
Each of these phases, however, was in itself incapable of modification
except for the possibility of doing a certain small amount of retouching;
nevertheless, by means of efficient management of the single printings
and by properly combining them, beautiful artistic effects could be
obtained. This, however, required an extraordinary amount of practice and
skill, and a very considerable expenditure of time, and it must also be
remembered that the failure of one of the last printings often destroyed
all the previous work. Also, in gum printing, to have a reasonable
expectation of success, the work must be thought out from the very
beginning and carried out in exact accordance with a plan from which it
was scarcely possible to deviate during the work, even when it became
apparent that the desired result could not be satisfactorily obtained.
The possibility of planning results during the course of the printing and
carrying them out directly on the print itself did not previously exist.
The first process to bring us nearer to this ideal and make possible a
freer method of working was oil printing. The technique of this process
consisted in sensitizing paper which had been coated with a layer of
gelatine, by means of a solution of potassium bichromate, and of printing
it under the negative. The yellowish image was then washed out; the
bichromate had, however, produced various degrees of tanning of the
gelatine, corresponding to the various densities of the silver deposit
in the negative. The lighter portions, which had been protected from
the action of light by the dense parts of the negative, retained their
original power of swelling and could therefore later absorb water. The
shadows, however, corresponding to the transparent parts of the negative,
were tanned, had lost their absorptive power, and had become incapable of
taking up water. Consequently, the high lights swelled up fully in water,
the shadows remained unchanged, and the middle tones showed various
degrees of swelling corresponding to the gradation of the negative. If
the print was blotted off and greasy inks spread upon it by means of a
properly shaped brush, the inks were entirely repelled by the swollen
high lights which had absorbed water, and completely retained by the
fully tanned shadows, while the middle tones, in proportion to the amount
of tanning, retained or repelled the greasy ink more or less completely.
In this process, for the first time, there was found a possibility of
changing various parts of the image absolutely at the worker’s will,
even during the progress of the work. By the use of harder or softer
inks it was possible to color the swollen high lights more deeply, or to
hold back the shadows so that they did not take up all the ink that was
possible. It was possible to leave certain parts of the print entirely
untouched and work up other parts to the highest degree; in short, oil
printing opened the way to free artistic handling of the print.
Thus, the oil process was the first photographic printing process in
which we were completely emancipated from the previous inflexibility
which ruled in all printing.
Nevertheless, a number of disadvantages attach to oil printing which
hinder its general use. The most important shortcoming of this process
is that bichromated gelatine as a printing medium can only reproduce
a comparatively short scale of tone values. The production of prints
from contrasty negatives is therefore impossible, for the shadows are
much overprinted before details appear in the high lights, or on the
other hand, there is no detail in the lights if the shadows are fully
printed. This difficulty can be only partly overcome by the most skilful
use of inks of various consistency. It is indeed possible to ink up
the lights by the use of very soft ink, but this does not replace the
missing details; and overprinted shadows, which it is tried to improve by
keeping down the quantity of ink applied, appear empty. Thus it happens
that most of the oil prints yet exhibited show a certain muddy family
likeness, which, at first, when the process was new, was considered to be
advantageous on account of the novelty of the effect, but later received
deserved criticism. A second disadvantage of the oil print is the fact
that it is not possible to observe the progress of the printing on the
bichromated gelatine film. The brownish image on a yellow background
is very deceiving, and it is usually necessary to determine the proper
amount of printing for each individual negative by actual experiment, and
to make additional prints by means of a photometer.
Another inconvenience of other previously known printing processes, to
which oil printing is also subject, comes from the fact that the great
majority of negatives are now made with small cameras. On account of
the extraordinary perfection of modern objectives, the small negatives
produced by modern hand cameras can be enlarged practically without
limit. The advantages of a portable camera are so considerable that large
and heavy tripod cameras have practically gone out of use, except for
certain special purposes. On the other hand, however, direct prints from
small negatives are, as a rule, entirely unsatisfactory from an artistic
standpoint. If we desire to use any of the previously mentioned positive
processes, including oil, to produce artistic effects, we must first make
an enlarged negative. This requires, in the first place, the production
of a glass transparency from the small negative, from which we may
prepare the desired enlarged working negative.
Various workers held various views as to whether this requirement were
a help or a hindrance, but it was universally accepted as a necessity.
The way from the plate to the enlarged negative, nevertheless, always
remained uncertain, tedious, and expensive. Simple as it may appear to
be, it includes a whole series of stages where it is possible to come
to grief. At every single step lurks the danger that undesired changes
of gradation in the negative may result from inaccuracy in exposure and
development, from the use of improperly chosen sensitive material, and
from various other causes, and even if these factors are all correctly
handled, there is still an unavoidable loss of detail. Therefore the path
from the small original negative to the enlarged negative necessary in
previously used processes is neither simple nor safe.
Naturally it was also necessary to travel this wearisome path in working
the oil process, when it was desired to make large prints from small
negatives.
When it was announced in England that Welborne Piper had discovered a
process which started from a finished silver bromide print instead of
from a gelatine film sensitized with bichromate, new vistas were opened.
If the process should prove to be practically useful, we could consider
that all the previously mentioned difficulties were overcome at a single
stroke.
The principle of this process, _bromoil printing_, is the removal of the
silver image from a finished silver bromide print by means of a bleaching
solution while, simultaneously with the solution of the silver image,
the gelatine film is tanned in such a way in relation to the previously
present image that the portions of gelatine which represent the high
lights of the image preserve their capability of swelling, while the
shadows of the image are tanned.
_Therefore the bromoil process is a modification of oil printing, based
not upon a bichromated gelatine film, but upon a completed bromide
print._ This represents extraordinary progress. The two previously
mentioned disadvantages of oil printing are completely avoided in the
bromoil process. We now have at our command the far longer scale of
tone values of bromide paper and we can use the great possibilities
of modification allowed by the highly developed bromide process. The
difficulties of printing are completely removed, for we have at our
command a perfectly visible image as a starting point. A further
advantage which can not be too highly estimated is inherent in the
bromoil process: _complete independence of the size of the original
negative_.
When I began my investigations in the field of bromoil printing, the
process had, as far as practical value went, only a purely theoretical
existence, as is the case in the early days of most photographic
processes. The fact that it was possible to produce images on a bleached
bromide print by the application of greasy inks was well established.
The practical application of the process was absolutely uncertain and
only occasionally were satisfactory results obtained. Most of the prints
produced in this way were flat and muddy. It is easy to understand
that the process could find no widespread popularity while it was so
incompletely worked out. The researches, which I then began, showed
that most bromide papers took up greasy inks after development by any
method and subsequent bleaching of the image. The pictures thus obtained,
however, were muddy, flat, and not amenable to control, and therefore
were less satisfactory than the bromide prints from which I had started.
During the course of my work, I have succeeded in obviating these
difficulties, in the first place, by preparing a satisfactory bleaching
solution, next, by determining what properties bromide paper must possess
in order to give perfect bromoil prints, and, finally, by working out
a series of other necessary conditions, which I have described in this
book and which must be adhered to if the process is to work smoothly and
certainly, and produce satisfactory results.
The bromoil process, which is now completely mastered, offers, in brief,
the following advantages:
Simplicity, certainty and controllability of the printing material;
Independence of the size of the negative and easy production of enlarged
artistic prints;
Freedom in the choice of basic stock and its surface;
The possibility of freely producing on the print any desired deviations
from the negative, during the work;
Full mastery of the tone values without dependence on those of the
negative;
Independence of daylight, both in printing and in working up the print;
The possibility of the most radical alterations of the print as a whole
and in part during the work;
Freedom of choice of colors;
The possibility of preparing polychromatic prints with any desired choice
of colors, and complete freedom in the handling of the colors;
The possibility of comprehensive and harmonious modifications of the
finished print;
The possibility of producing prints on any desired kind of non-sensitized
paper by the method of transfer.
The description of working methods will be divided into the following
phases:
I. Production of the bromide print;
II. Removal of the silver image;
III. Application of the ink;
IV. After-treatment of the finished print.
CHAPTER I
PRODUCTION OF THE BROMIDE PRINT
_Failures in the bromoil process in the great majority of cases can be
ascribed to the fact that the basic bromide print was not satisfactory._
Therefore the method of preparation of the bromide print or enlargement
deserves the most careful consideration, for the bromide print is the
most important factor in the preparation of a bromoil print. _The
beginner, especially, can not proceed too carefully in making his bromide
print._
Because of the extraordinary importance of this point, we must first
define what is here meant by a perfect bromide print.
In deciding how to produce a satisfactory bromide print as a basis for a
bromoil, we must exclude from consideration esthetic or artistic grounds.
_The bromide print must be technically absolutely perfect, that is, it
must have absolutely clean high lights, well graded middle tones, and
dense shadows._ Especial stress must be laid on the brilliancy of the
high lights. It is best to compare these high lights with an edge of the
paper which has not been exposed and is not fogged or, even better, with
the back of the paper. The highest lights should show scarcely a trace
of a silver precipitate and must therefore be almost as white as the
paper itself. _Negatives which do not allow of the production of prints
as perfect as this should not be used while the bromoil process is being
learned._
This apparently superfluous definition of a perfect bromide print has to
be given in this way, because it only too often occurs in practice that
_the worker himself is not clear as to what is meant by the expression,
perfect bromide print_. This may be partly ascribed to the fact that the
silver bromide process—whether rightly or wrongly need not be determined
here—has not been properly appreciated among amateurs who are striving
for artistic results. Bromide printing has frequently been considered not
to be satisfactory as an artistic means of expression, and has therefore
been considerably neglected. In many quarters it is considered as just
good enough for beginners.
Nevertheless, the bromide process is _per se_ an uncommonly flexible
method and gives, even with a very considerable amount of overexposure
or underexposure, that is, even when very badly handled, results which
are considered usable. It is even possible that an improperly made
bromide print, one for instance, which is soft and foggy, might in some
circles be considered as esthetically more interesting than a perfect
print. This is an undeniable advantage of the process. It may also
become a danger, if an imperfect bromide print is used as a starting
point in the bromoil process. If anyone is not sure on this point, let
him compare his own bromide prints with such samples as are frequently
shown by manufacturers in window displays and sample books. He will then
see what richness of tones and wealth of gradation are inherent in the
process. _If, however, an imperfect silver bromide print is used as a
starting point for a bromoil, it can not be expected that the latter will
display all the possibilities of this process._ If the bromide print is
muddy, the work of inking will be difficult, and it will be impossible
to obtain clean high lights. If it is underexposed and too contrasty,
it can not be expected that the bromoil will show details in the high
lights which were lacking in the bromide print. If the worker himself
does not know that his silver bromide print is faulty, he is inclined
to ascribe the difficulties which he finds in making the bromoil print
and his dissatisfaction with the results, to the bromoil process itself.
Most of the unsatisfactory results in bromoil work must be ascribed to
the imperfect quality of the bromide print which is used, and this is
the more important as this lack is not perceptible to the eye after the
bleaching is completed. _Whoever, therefore, desires to successfully
practice bromoil printing, must first decide impartially and critically
whether he actually knows how to make bromide prints, and must acquire
full mastery of this process._
The technically perfect bromide print made from a properly graded
negative can, as will later be described, have its gradations changed in
the bromoil process without any difficulty, and thus be made softer or
more contrasty. The advanced bromoil printer who is a thorough master of
the technique of the process will therefore easily be able to work even
with poor negatives; when making his bromide prints from such negatives,
he will consider the ideas which he intends to incorporate in the bromoil
print and will make his bromide print harder or softer than the negative
and at the same time retain the necessary cleanness of the high lights.
The best starting point for a bromoil print, however, especially for the
beginner, is and must be a bromide print as nearly perfect as possible.
A suggestion for the certain obtaining of such prints may be added here.
When we are working with a negative with strong high lights, judgment
as to the freedom of the bromide print from fog by comparison with an
unexposed edge is not difficult. This is not the case with negatives
which show no well marked high lights. In such cases it is advisable to
_determine what is underexposure_ by making test strips in which details
in the high lights and middle tones are lacking and, working from this
point, determine by gradual increase of exposure the correct time which
gives a perfectly clean print.
THE CHOICE OF THE PAPER.—One of the most important problems is to find
a suitable paper for the process. Not all of the bromide papers which
are on the market will give satisfactory results. _It is only possible
to use papers whose swelling power has not been too completely removed
in process of manufacture by the use of hardeners._ The principle of
the bromoil process is that a tanning of the gelatine shall occur
simultaneously with the bleaching of the silver bromide image. As we
have already remarked, this does not affect the high lights and leaves
them still absorbent, while the shadows are tanned and therefore become
incapable of taking up water. The half-tones are tanned or hardened to an
intermediate degree and therefore can take up a certain amount of water.
_Therefore, in place of the vanished silver image, we get a totally or
partially invisible tanned image in the gelatine film._
The variously hardened parts of the gelatine film, corresponding to the
various portions of the vanished bromide image, display the property
acquired through different degrees of tanning by the fact that the
portions of the gelatine which remain unhardened and which correspond
to the high lights of the silver image formerly present, absorb water
greedily. Consequently they swell up and acquire a certain shininess,
because of their water content; in addition they generally rise above
the other parts of the gelatine film, which contain little or no water,
and give a certain amount of relief when they are fully swelled. The
portions of the film in which the deep shadows of the bromide image lay
are completely tanned through, can therefore take up no water, and remain
matt and sunken. This graded swelling of the gelatine film becomes more
apparent, the higher the temperature of the water in which the film is
swollen.
If, however, the paper was strongly tanned in the process of manufacture,
the gelatine has already lost all or most of its swelling power before it
is printed and, although the bleaching solution in such cases can indeed
remove the silver image, it can no longer develop the differences of
absorptive power which are necessary for a bromoil print; for, although
the bleaching solution can harden an untanned gelatine layer, it cannot
bring back the lost power of swelling to a film which is already hardened
through and through.
Therefore bromide papers which have already been very thoroughly hardened
in manufacture show no trace of relief after bleaching, and very slight,
if any, shininess in the lights. This is the case especially with those
white, smooth, matt, heavyweight papers which are especially used for
postcard printing. When such papers are taken out of the solutions, as
a rule, these run off quickly and leave an almost dry surface. It is
generally not possible to make satisfactory bromoil prints on such
papers. It is true that the image can be inked by protracted labor;
it is, however, muddy and flat and, as a rule, cannot be essentially
improved even by the use of very warm water. Other types of bromide paper
which have not been so thoroughly hardened may show no relief after
bleaching, yet, after the surface water has been removed, they do show
a certain small amount of shininess in the high lights when carefully
inspected sidewise. With such papers the necessary differences of
swelling can generally be developed if, as will later be more completely
described, they are soaked in very warm water or in an ammoniacal
solution. It is rare to find in commerce silver bromide papers which
have not been hardened at all, or only very slightly hardened, in their
manufacture. Such papers, because their films are very susceptible to
mechanical injury, are not likely to stand the wear and tear of the
various baths. On the other hand, as a rule, they usually produce a
strong relief even in cold water, and therefore tend to produce hard
prints. The greatest adaptability for bromoil printing may be anticipated
from bromide papers which are moderately hardened during manufacture.
To determine whether a given brand of bromide paper is suitable for
bromoil work, an unexposed sheet of the paper should be dipped in
water at a temperature of about 30° C. (86° F.) and the behavior of
the gelatine film observed. If this swells up considerably and becomes
slippery and shiny, the paper has the necessary swelling power and can be
used with success.
On account of the great variety of bromide papers which are on the
market, we have a very wide choice as regards the thickness and color of
the paper and the structure of its surface. It may be remarked here that
papers of any desired surface, even rough and coarse grained papers, can
be used for bromoil printing, as easily as papers with a smooth surface.
The difficulties experienced with very rough surfaced papers in some
other processes do not exist in bromoil. Because of the elasticity of
its hairs, the brush carries the ink as easily into the hollows of the
surface as to its high points.
The thickness of the paper is of no importance in bromoil printing,
except that the handling of the thicker papers is easier, because they
lie flatter during the work and distort less on drying; also, as a rule,
thick papers are easier to ink.
_Gaslight papers_ can also be used if their gelatine films satisfy the
above mentioned requirements. Therefore we have the widest possible
choice in the printing materials for bromoil.
A great number of bromide papers of different manufacturers are well
suited for bromoil printing; it is, however, advisable to make a
preliminary investigation as to the amount of hardening they have
undergone, for it occasionally happens that different emulsions of the
same brand show quite different grades of hardening, so that on one
occasion it is possible to make bromoil prints on them without the least
difficulty, while the same paper at another time may absolutely refuse to
take the ink. On account of the great popularity of the bromoil process
in recent years, it can be easily understood that some manufacturers
might seek a wider sale for their products by claiming for them a
special suitability for this process. It is therefore a wise precaution
to previously test even those brands which are advertised as specially
adapted for bromoil printing, and not to depend too much on such claims.
DEVELOPMENT.—The processes of tanning in the film of a bromide print,
produced by the bleaching of the silver image, which will be described
later, are of an extremely subtle nature. We must therefore endeavor to
avoid all causes for damage in this process and especially everything
which tends to harden the whole film even to the slightest degree. Any
tanning, which affects the whole gelatine film, has the same effect
as general fog in a negative. It is well known that almost all the
developers used in photography have more or less tendency to harden the
gelatine film. A very considerable damage to the bromoil print through
the use of a tanning developer might naturally be imperceptible to
the eye. Yet this may at times manifest itself in a very undesirable
and disturbing form, especially when the bromide paper has been so
much hardened in manufacture that it possesses only just the necessary
qualification for bromoil printing. It may then happen that the last
remainder of swelling capacity can be taken from the paper by the use of
a tanning developer. However desirable it might be and however it might
simplify the process to be able to use any desired developer in producing
the bromide print, to avoid trouble it must be observed that the use of
developers which tan the film may seriously influence the result, even
though it is possible to get some kind of prints in many cases. _If the
worker is absolutely sure that the bromide paper which he is using is not
strongly hardened and is therefore well suited for bromoil printing, he
may undertake development with any one of the ordinary developers which
he prefers._
The developers, which do not exercise a hardening influence on
the gelatine, are the iron developer and amidol (diamidophenol
hydrochloride). As the iron developer is not really suited to this
purpose on account of certain unpleasant qualities inherent in it, it is
advisable to use amidol for the development of bromide paper for bromoil
printing whenever possible, and the best developer is composed as follows:
Amidol 1.7 g 12.3 gr.
Sodium sulphite, dry 10 g 77 gr.
Water 1000 ccm 16 oz.
The sodium sulphite is first dissolved in water, and the easiest way
is to pour the necessary quantity of water into a developing dish and
sprinkle the pulverized or granular dry sodium sulphite into it while the
dish is constantly rocked; solution takes place almost instantly under
these conditions. Larger lumps, which would stick to the bottom of the
dish, must be immediately stirred up. As soon as the sodium sulphite
is dissolved, the amidol should be added and this will also dissolve
immediately. The addition should be made in the order described, for,
if the amidol is dissolved first, the solution is often turbid. If dry
sodium sulphite is not available, double the quantity of crystallized
sulphite may be used.
The amidol developer should be freshly prepared each time that it is
used, as it does not keep in solution. The measurement of the quantities
of amidol and sulphite given above does not need to be made with the most
painstaking care, as small variations in the quantities are unimportant.
In using amidol developer the greatest care must be taken to avoid
allowing amidol powder, in even the smallest quantity, to come into
contact with the bleached print ready for bromoil printing. Even the
finest particles of amidol, although invisible to the naked eye, will
produce yellowish brown spots on the gelatine which penetrate through
the film and into the paper itself. These dots and spots, especially if,
as is usual, they occur in large numbers, will make the print completely
useless, and it is impossible to remove them.
If amidol developer is not available, _any other developer which is
desired_ may be used. As we have already stated, however, certain
possibilities of failure are to be anticipated, but will not necessarily
occur.
_Every effort should be made to produce a bromide print as perfect as
possible, with clean high lights._
The best bromide prints or enlargements for bromoil printing are those
which are _correctly exposed, but are not developed out to the greatest
possible density_. A print which is thus fully developed is very
satisfactory as a bromide but offers certain difficulties in bromoil
printing, which will be described later. _Therefore the development
should be stopped as soon as the lights show full detail without any
fog, but before the shadows have reached full density._ The deepest
shadows should then be of a deep greyish black, but should not be clogged
up. When a bromide print is properly exposed, there is sufficient time
between the appearance of the details in the lights and the attainment
of the deepest possible black in the shadows to easily select the proper
moment for cessation of development. It is, however, desirable not to
go beyond this stage of development, for the reason that _a very dense
silver deposit distributed completely through the gelatine emulsion to
the paper support is not easily bleached out_. When this difficulty
occurs, the bleaching solution is generally, but incorrectly, blamed for
it. If, in spite of this difficulty, complete bleaching is attained, the
shadows of the image usually retain a yellowish color which cannot be
removed by the baths which follow the bleaching. If it is intended to ink
up the whole surface of such a print, this discoloration of the shadows
is not important, for it will be completely covered by the ink. But if
the print is to be treated in a sketchy manner, and some parts of its
surface are not to be inked, this cannot be successfully done on account
of the yellowish coloring of the shadows.
_Underexposure_ must be carefully avoided, for details which are not
present in the bromide print will, of course, not appear in the bromoil
print.
_Overexposure_ will occasionally give usable results, if the development
of the overexposed print is stopped at the proper point. In such cases,
we must usually expect some deposit in the high lights and consequently
a certain fogging of the image, though this can often be overcome, at
least partly, by swelling the print at a higher temperature. Perfect
prints cannot be expected, if the basic print is lacking in quality.
If the overexposure is not too great, the print can be improved to a
certain extent by clearing it in very dilute Farmer’s reducer. Treatment
with this reducer has no deleterious effect on the later processes. The
Farmer’s reducer should only be used for a slight clearing up of too dark
parts of the bromide print; for this purpose the parts of the moist print
which are to be reduced should be gone over with a brush dipped in very
dilute reducer and immediately plunged into plenty of water, to avoid any
spreading of the reducer into other parts of the image.
_Developing fog_ should naturally be avoided as much as possible.
Fogging of the bromide print is caused by the formation of a more or
less dense silver precipitate without any relation to the image over
the whole surface of the print. As the bleacher takes effect wherever
metallic silver is present in the film, the result in such cases is a
general tanning of the film, which is detrimental to the production of
the necessary differences in swelling power in the gelatine. The tanned
gelatine image is then also fogged.
_Consequently the best results may be obtained from very brilliant, but
not excessively developed, bromide prints._
We must also _avoid falling into the opposite extreme in the development
of the bromide print, by getting too thin prints lacking in contrast_.
In prints which are too thin, only a very small quantity of metallic
silver has been reduced in the development, and this lies wholly on
the surface of the film. Such prints usually show full detail, but the
contrasts between the lights and the shadows are too small. Since the
tanning produced by the later bleaching occurs because of the presence
of metallic silver in the film, and since its intensity depends on the
quantity of this silver, we cannot obtain the necessary difference
in swelling power by bleaching the film of prints which are too thin
because of insufficient development. The result is a weak tanned image
in the gelatine film; bromoil prints thus produced can consequently only
exhibit a very short scale of tone values, and this cannot be essentially
lengthened by the use of the bromoil process alone. Such bromide prints
may find a special application in combination transfers, which will be
described later. It is also possible, under certain circumstances, to
use incomplete development as a method for producing soft bromoil prints
from contrasty negatives.
CONTROL OF THE SILVER BROMIDE PRINT.—Although in bromoil printing the
most various renderings can be obtained from a perfect bromide print,
by variation of the temperature of swelling and by proper handling of
the inking, it is also possible, under some circumstances, to vary
the final result by proper treatment during the making of the bromide
print, especially when we are not dealing with normal negatives. If,
for instance, we have to deal with a very thin negative, it is possible
that even the extreme possibilities offered by the bromoil process are
not sufficient to insure the attainment of the desired modulation, for,
as will later appear, the possibility of increasing the difference in
swelling in the film is limited by the limited resisting power of the
gelatine. In such cases, we must take advantage of the accumulation of
all possible aids and therefore, in making the bromide print, do all
that is possible in order to bring out desired objects, which are only
indicated in the negative and do not show sufficient detail.
_Therefore, if we desire to increase the contrast of the negative in the
final print_, we should use a harder working paper and add potassium
bromide to the developer.
_If we desire to get soft prints from a contrasty negative_, we may
use different methods. The simplest way is the use of a very rapid and
consequently soft working paper. Ordinarily, however, this method is not
sufficiently helpful. We must therefore also use suitable methods in
later steps of the process, such as making the difference in swelling
in the gelatine layer as small as possible in order to bring down the
contrast, or inking up with soft inks.
A very reliable process for the production of soft prints or
enlargements, even from contrasty negatives, is the following: the
proper exposure for the densest portions of the negative should be first
determined by means of a trial strip; then a full sized sheet of paper is
exposed for exactly the time which has been determined, soaked in water
until it is perfectly limp, and then placed in the developer. As soon as
the first outlines of the image appear, the print is placed in a dish of
pure water and allowed to lie there, film down. As soon as development
has ceased, the print is taken out of water, dipped into the developer
for an instant, and then immediately put back into the water. This method
requires considerable time for full development, but produces prints or
enlargements of especial softness. In this process, the developer which
is absorbed by the film is soon exhausted in reducing the heavy deposit
in the shadows, so that their development ceases, while enough developer
still remains unexhausted in the other portions of the image to keep on
developing. With very dense negatives, developer warmed to 25° C. (77°
F.) can be used for the production of soft prints, but it must be very
much diluted and carefully used, for development proceeds very quickly.
Very soft prints may also be obtained by bathing the exposed bromide
prints for about two minutes in a one per cent solution of potassium
bichromate before development. This solution is thoroughly washed out of
the print, and it is then developed.
Yet with very hard negatives all these remedies frequently fail, because
the high lights are almost completely opaque to light because of their
density. In such cases the negative itself must be improved. The ammonium
persulphate reducer usually recommended for such plates, which acts more
strongly on the lights than on the shadows, is, however, too uncertain in
its action and may imperil the negative. It is better to adopt _Eder’s
chlorizing method_, which enables one to improve too contrasty negatives
in a convenient and certain manner. The principle of this process is as
follows: the metallic silver of the negative is converted into silver
chloride, which is again developed. This redevelopment is accomplished in
such a way that the silver chloride on the surface of the film is first
reduced to metallic silver; if development is continued, the reduction
is continued to the bottom of the film. The delicate details, lying on
the surface of the film, are thus first developed, while development of
the overdense high lights, in which the silver deposit extends right
through to the glass, is finished only after some time. It is therefore
possible to stop development at the instant at which the shadows and
half-tones are completely redeveloped, while the overdense high lights
are, for instance, only half developed, and therefore only half consist
of metallic silver, the lower half being still silver chloride. If the
development is interrupted at this stage and the negative placed in a
fixing bath, the still undeveloped silver chloride is dissolved. The
shadows and half-tones thus retain their original values, and only the
overdense deposits in the shadows are reduced. If the development is not
stopped at this stage, but is carried through to completion, the negative
is obtained unaltered, and the process can be repeated. If the second
development is stopped too soon, the negative may be endangered and a
very thin negative, lacking in contrasts, obtained.
The practical application of the chlorizing process is effected by
bleaching the negative in the following solution:
Cupric sulphate 100 g 1 oz.
Common salt 200 g 2 oz.
Water 1000 ccm 10 oz.
As soon as the negative is completely bleached, which should be judged
not only by transmitted light but also by examination from the glass
side, it should be well washed and immersed in a slow-acting developer.
All these processes can be carried out in daylight, and the second
development of the negative is best controlled by frequent examination
of the glass side. Development should be stopped when the shadows and
half-tones are blackened, and there is still a whitish film of silver
chloride in the high lights. Observation of the negative by looking
through it is not advisable, for the negative very soon appears dense
by transmitted light, because the metallic silver formed in development
masks the silver chloride. As soon as the development is considered to
have gone far enough, the plate should be rinsed and then fixed and
washed in the usual manner. After a few trials, the judgment of the
correct stage at which to stop development presents no difficulty.
I ordinarily use the chlorizing process in the following way, which
practically excludes any possibility of failure: the negative is
completely bleached in the solution just mentioned, and then washed
for five minutes. It is then developed in any desired developer until
it shows by transmitted light practically the same density, though in
a brownish color, as it had before chlorizing. It is then rinsed off,
placed in a solution of hypo, _not stronger than two per cent_, and
carefully watched by light passing through the plate; it is taken out as
soon as the desired stage is reached, well washed, and dried. In this
modification of the chlorizing process the condition of the plate can be
observed at every stage. The final negative, to be sure, does not consist
of pure metallic silver, but as a rule of a combination of silver and
silver chloride; but such negatives are sufficiently permanent for making
prints and enlargements on bromide paper.
It is also advisable to lessen the harsh contrasts in a normal negative,
either by masking the more transparent parts on the glass side, or by
holding them back in printing or enlarging. Briefly, every possible means
should be employed in order to obtain as good and harmonious a bromide
print as possible.
_The beginner is strongly recommended, however, in his first trials with
bromoil, to start as far as possible with normal negatives and correct,
and especially very clean, bromide prints._ The use of this process for
the improvement of the results from difficult negatives should be left
for more expert workers.
It is often desired to provide landscapes with clouds, and this can
be easily attained if enlargements are used as the basis for bromoil
prints. Acceptable results are given by a process, which has often been
recommended. This is, after blocking out the sky on the negative, to
enlarge the landscape, develop the print and again place it while still
wet on the enlarging screen and expose for the clouds, disregarding the
existing image, and then develop the clouds.
I might describe here another process for obtaining clouds, because it
is especially suitable for the bromoil process. If there is no object in
the negative which is cut by the upper edge of the plate, it is extremely
easy to introduce clouds into such a landscape, and at the same time
lengthen out the picture at the top. A cloud negative suitable for the
landscape is chosen, and the relative exposures for the landscape and
clouds found as accurately as possible by test strips. The landscape
negative is then focused on the enlarging screen so that there is plenty
of paper above the upper edge of the plate, and then the exposure is made
while the upper part of the paper is covered with a card, which is kept
moving constantly between the light source and the enlarging screen, so
that the upper edge of the plate is not imaged on the screen. After the
exposure is finished, the paper is shifted down on the screen until the
upper edge of the paper comes at the place which was previously occupied
by the edge of the plate, the landscape negative is changed for the
cloud negative, and the clouds are exposed on the upper and hitherto
unexposed part of the enlarging paper, while the landscape is protected
from exposure by means of a piece of card, shaped like the previous one
for the sky, and continually moved to avoid a sharp line of separation.
In the subsequent development a perfectly uniform picture is obtained, in
which there should be no visible trace of its compound nature.
Obviously, in the preparation of the bromoil print, it is advisable
to employ to the utmost the many possibilities which bromide printing
offers. Thus too thin parts of a negative may be held back by proper
blocking out on the back and numerous other possible modifications,
which have been described in textbooks and technical journals, but which
cannot be further dealt with here, may be profitably employed.
FIXATION.—_The developed bromide print should be well rinsed and fixed in
the usual way._ If the rinsing is omitted or is too superficial, complete
or partial reduction phenomena may occur in the fixing bath, and make the
print unusable.
The bromide print should be left in the hypo solution for about 10
minutes, and care should be taken, if several prints are simultaneously
treated, that they do not stick to one another. Then should follow
thorough washing for removal of the hypo; if traces of hypo remain in
the film, the subsequent bleaching is rendered more difficult, as the
image does not disappear but only turns brownish. While it is feasible
to subject the bromide print to the bleaching process, as soon as it
comes from the washing, _an intermediate drying is an advantage_; for the
gelatine gains greater resistance by this drying.
CHAPTER II
THE REMOVAL OF THE SILVER IMAGE
BLEACHING.—The bleaching process has the purpose of making the bromide
print, correctly prepared according to the previously described method,
suitable for the bromoil process. To this end the silver image must
be made to disappear and in its place that condition of the gelatine
produced which renders it possible for it to take up the greasy ink.
_The bleaching solution has, therefore, two functions: it must remove
the metallic silver, imbedded in the gelatine film, which forms the
bromide image, and at the same time cause a tanning of the gelatine film
corresponding to the image that disappears. In the place of the silver
image there then exists an invisible tanned image in the gelatine film._
There are a large number of chemical compounds known to photographic
technique, which enable us to dissolve out the metallic silver imbedded
in the gelatine film. Such are, for example, the many reducers which have
found practical application. Many of these chemicals also cause changes
in the gelatine simultaneously with the solution of the silver. But not
one of the hitherto known bleaching solutions possesses the double power
required of it: solution of the silver image and corresponding tanning
of the film. Some produce too great a tanning which acts upon the whole
film, and the result in inking-up is muddy flat prints, which do not lend
themselves to artistic modification. With other bleaching solutions a
differential tanning of the gelatine is produced, but at the same time
they so alter the surface of the gelatine that it becomes glossy all
over, and only takes even soft inks with difficulty.
My experiments have led to the compounding of a bleach which completely
fulfils the requirements set for it; the silver image is quickly and
completely removed, while simultaneously a tanning of the film, strictly
analogous to the disappearing image, is effected; easier and more
certain inking-up is rendered possible, and besides this the advantage
is obtained that the differences of relief, produced in the gelatine by
the bleaching process, can be influenced to a wide degree by varying the
temperature of the water. The composition of this bleaching solution,
which prepares the gelatine film in the most perfect manner for the
bromoil print, is as follows, three stock solutions being required:
I. Cupric sulphate 200 g 2 oz.
Water 1000 ccm 10 oz.
II. Potassium bromide 200 g 2 oz.
Water 1000 ccm 10 oz.
III. Cold saturated solution of potassium bichromate.
A concentrated bleach is made by mixing:
Solution I. 3 parts
Solution II. 3 parts
Solution III. 1 part
To every 100 ccm of this mixture should be added 10 drops of pure
hydrochloric acid (10 drops to 3½ oz.). This concentrated bleach will
keep indefinitely and should be diluted before use with three to four
times its volume of water. The use of a more concentrated solution is not
advisable, as irregularities frequently occur in consequence of too rapid
bleaching, especially towards the margins of the prints.
The color of the concentrated bleach is green, or when diluted,
yellowish; the solution must be absolutely clear. When the stock
solutions are mixed there is usually some cloudiness, but this is
cleared up by the hydrochloric acid. By standing for a long time at low
temperatures a precipitate is sometimes formed, but this is of no moment.
The compounding of this bleach should be made with the greatest accuracy.
Inaccuracies or modifications in its composition are serious, because
although the solution does not lose in bleaching power, yet the invisible
tanning action is then often not completed in the desired manner. Too
great an addition of hydrochloric acid for example, accelerates the
process of bleaching, but the inking-up of prints thus bleached is
frequently difficult. If the bleaching of the shadows of the bromide
prints goes on slowly, the reason as a rule lies in the fact that the
prints were overdeveloped and have an excessively dense silver deposit.
The bromide prints should be immersed in this bleaching solution,
after previous soaking in cold water. If they have been correctly
made, the image rapidly grows weaker and after a few minutes its
greyish-black color changes into a pale citron yellow. If the bromide
print was developed too far, the bleaching takes rather longer, as
the shadows, developed right through to the base, require a lengthy
period for solution. If several prints are to be bleached at once,
the best procedure is to place one print in the solution and turn it
film side down when the first traces of bleaching are noticeable.
Then the next print should be immersed with the film up and by thus
proceeding gradually it is possible to bleach a large number of sheets
simultaneously in the one dish. Continual movement will prevent the
formation of air bells. If air bells adhere to the film, they protect
those places from the action of the bleach and dark points or spots of
unchanged metallic silver remain, the subsequent bleaching of which
naturally prolongs the process. The same applies to prints which lie on
top of one another.
With too slow bleaching, the hydrochloric acid may be gradually
increased, _at the most_ to double that prescribed; one should not hasten
the bleaching process by warming the solution. The bleaching is rapidly
effected in warm solutions; yet generally the film of moderately hardened
papers is so altered that they swell up too much even in cold water and
take the ink badly or not at all. The dilute bleaching solution will keep
and may be used repeatedly as long as it acts; when it becomes exhausted,
the slowing up of the bleaching cannot be hastened by the addition of
hydrochloric acid. The chemical reactions in the bleaching bath are,
according to Dr. P. R. von Schrott, as follows:
2CuBr₂ + Ag₂ = 2AgBr + Cu₂Br₂
The cuprous bromide, Cu₂Br₂, which is formed, reduces the bichromate as
follows:
3Cu₂Br₂ + 6CrO₃ = 3CuBr₂ + 3CuCrO₄ + Cr₂O₃.CrO₃
_It sometimes happens that bromide prints, in spite of long immersion in
the bleaching solution, apparently will not bleach and only change their
color to brown._
The reason for this usually unimportant phenomenon is, as a rule, that
such prints have not been sufficiently washed and still contain hypo.
It may also happen that prints which have lain on top of each other in
washing are badly washed in parts; then the image bleaches, _but the film
shows dark patches or streaks at those places which still contain hypo_.
Such apparently unbleached prints should be left for about 10 minutes in
the bleaching solution; _the disturbing coloration, whether of the whole
picture or only of parts, disappears completely in the subsequent baths_,
even when the image had apparently remained at full strength.
If such a print, apparently not bleached or spotty, is immersed in the
sulphuric acid bath mentioned below, the discoloration of the film is
quickly removed by its action; the print then often passes through a
phase in which it appears to be a negative, the secondary image becoming
visible on the yellow ground, and then bleaches out completely. With such
prints it may also happen that it is only noticed after removal of the
stain that unbleached traces of the silver image still remain. Then the
bleaching must be repeated.
If the color of the bromide print only changes to brown even after
protracted immersion in the bleaching solution, otherwise retaining full
gradation, and remaining unchanged even in the sulphuric acid bath,
though it bleaches out in the hypo, the print cannot be inked. The reason
for this difficulty is improper composition of the bleaching solution, or
occasionally improper development and fixation of the bromide print. It
may also be due to excessive use of the bleaching solution; 3 to 4 ccm
(50 to 70 minims) of concentrated bleaching solution should be allowed
for every 13 by 18 cm (5 by 7) print.
Obviously all these processes may be carried out by diffused daylight.
The bleached-out prints should be repeatedly washed, until the drainings
are quite clear, and should then be immersed in the following bath:
Sulphuric acid, pure 10 ccm 77 min.
Water 1000 ccm 16 oz.
_In this bath any remaining color disappears quickly and completely_, and
prints, which have apparently wholly or partially resisted bleaching,
are also very rapidly decolorized in this bath. Any spots and streaks
also disappear. If, however, there is anything left, then the bleaching
was not complete, and unreduced metallic silver remains in the film.
_After the sulphuric acid bath the prints should show the pure color of
the paper base; the film side ought to be hardly different from the back
in color._ With prints that have been overdeveloped, a certain slight
variation of color remains in the film, which, however, in no wise
prejudices the inking-up. If there are still some spots, they are usually
due to a slight precipitate lying on the surface of the film, which can
be easily swabbed off. When this point of colorlessness is reached, and
it usually requires only a few minutes, it is useless to leave the prints
longer in the acid bath. They should be washed in repeated changes of
water and immersed in the following fixing bath:
Hypo 100 g 1 oz.
Water 1000 ccm 10 oz.
The use of this fixing bath is essential and is based on the following
considerations. During the bleaching process a secondary silver bromide
image is formed in the gelatine film. This secondary image is not visible
on white and yellowish bromide papers, because it is whitish-grey. If a
bleached print, which has not been fixed, is exposed for a long time to
daylight a distinctly visible blue-grey image is formed, which naturally
is troublesome in the further operations. This secondary image of silver
bromide is completely removed, however, by the fixing bath.
The ordinary acid fixing baths can also be used without disadvantage
for fixing. If the sulphuric acid is not sufficiently washed out,
decomposition of the fixing bath may ensue, which will be made apparent
by the unpleasant smell, and which is prejudicial to the action of the
bath. Care should be taken that the prints do not stick to one another
in the fixing bath and that they are thoroughly fixed out, as the
secondary bromide image that is not removed will make its appearance in
insufficiently fixed places and may cause darker patches.
Washing then completes the preliminary preparation of the prints.
For the sake of completeness it should be mentioned that the prints may
be immersed in the bleaching solution in the darkroom after the first
development, and can be fixed after the solution of the silver image.
This shortened process is, however, uncertain and can not be recommended.
THE INTERMEDIATE DRYING.—_After the bleaching process outlined in the
previous section the print must be dried without fail._ While drying
after the development and fixation of the bromide print is advisable but
not absolutely necessary, _the intermediate drying after bleaching is
of the greatest importance_. It is possible that the later operations
may be successful in spite of neglect of this recommendation. As a rule,
however, various mishaps occur when the intermediate drying is omitted.
In many cases the ink can only be caused to adhere with difficulty, in
others, not at all; sometimes the inking will proceed up to a certain
point and then suddenly completely stop. Sometimes the image appears
as a negative, that is to say, the ink is taken up by the high lights
and rejected by the shadows. All these failures will be obviated by the
intermediate drying at this stage. Whether this intermediate drying takes
place rapidly or slowly is practically immaterial; naturally it ought not
to be so prolonged that the gelatine suffers.
The prints thus prepared can either be again soaked in water and
immediately worked up, _or kept and treated at any time_. It is very
convenient, especially for an amateur, to have a stock of such ready
prepared and dry prints, because he is then in a position to work when
he finds time and opportunity. The prints, prepared and dried as has
been described, will keep indefinitely. With correct treatment there can
be seen on the gelatine film of the dry print scarcely a trace of the
bleached-out image; only in the very deepest shadows a slight coloration
of the film, tending to grey, can sometimes be noticed. It is advisable,
therefore, to mark the print on the paper side before bleaching, as
otherwise it is subsequently difficult to distinguish this.
Before we go any further, the whole preliminary process is summarized
once more:
Development,
Fixation,
Washing,
Bleaching,
Short washing,
Sulphuric acid bath,
Short washing,
Fixation,
Washing,
Intermediate drying.
CHAPTER III
THE INKING-UP
THE PRODUCTION OF THE DIFFERENTIAL SWELLING.—In the chapter on the
bleaching we fully explained the processes which take place in the
gelatine film under the action of the bleaching solution, and that
the most important result of the bleaching process, aside from the
disappearance of the silver image, is the formation of different degrees
of swelling corresponding to the primary image, which in their totality
form the tanned image produced in place of the photochemical image by the
bleaching.
_For the success of the bromoil print, it is now of the utmost importance
that the different capabilities of swelling, now latent in the gelatine
film_, should be satisfactorily utilized. It is obviously possible to
produce this swelling in very different degrees. The colder the water
used for the swelling, the smaller the difference between the lights
and shadows, while the warmer the water the more this difference is
accentuated. If, for example, a print prepared for the bromoil process
is placed in _cold water_ and allowed to swell for some minutes, the
existing capacity for swelling will only be excited to a slight degree.
The high lights of the invisible image only take up a little water,
and when dry are differentiated from the shadows under oblique visual
examination by a very delicate gloss or not at all. If this picture is
now worked-up with greasy ink, a print is obtained with _a short scale
of gradation, and its tone values are usually less satisfactory than
those of the original bromide print_. If, on the other hand, the print
is placed in _very warm water_, the swelling of the gelatine reaches
a maximum. The high lights are very much swollen, even the half-tones
are somewhat raised, and the shadows, which do not absorb water, appear
sunken. The result of the swelling in such warm water in this case is
the formation of a very pronounced relief, that is not only visible, but
is almost perceptible to the touch. If such a picture is inked up, a
bromoil print is obtained, _the contrasts of which are much stronger than
those of the original bromide print_. Between these two extremes there is
obviously a whole series of intermediate stages, the suitable employment
of which permits of the most varied gradations.
As already mentioned, the capacity for swelling of the different makes
of bromide papers is not the same in baths of the same temperature. This
fact, however, argues neither for nor against the usefulness of the
various bromide papers. It makes necessary, to be sure, a certain care
in the use of a paper, the qualities of which are unknown. If one has
to deal with such a paper, the prepared print should first be soaked in
quite cold water; it should then be removed from the water, placed on
a support, dried in the manner to be later described, and examined by
oblique illumination as to whether the high lights show by a slight gloss
that they have absorbed water. This will be the case if the image shows
well swollen high lights; if they are not present, it will hardly be
possible to find distinctly glossy places. In any case one may begin with
the inking-up, prepared, as will be explained later, to increase the
swelling if necessary during the inking-up by immersion in warm water. If
on the other hand, the print, when taken from the cold water, distinctly
shows places where differences of swelling are shown by a gloss or even
a delicate relief in the film, the work may be proceeded with, without
further trouble.
Under any circumstance one should be careful at first in the production
of the differential swelling. _There should rather be no relief than too
pronounced a one_; for differences of swelling that are too small can be
easily and satisfactorily increased during the work; on the other hand it
is scarcely possible again to reduce too strong a relief. While learning,
or when using an unfamiliar brand of paper, it is therefore advisable
to allow the sheet to swell first in cold water and to carefully begin
the inking-up. Only if this is not satisfactory, should a warmer bath
be used and the inking again tried. This method is, however, dealt with
more fully in the section of Chapter III, entitled “Different Methods of
Working” (page 85).
THE PROPERTIES OF THE RELIEF AND ITS INFLUENCE ON THE CHARACTER OF THE
PICTURE.—In order that the following explanations may be understood,
an important property of the prepared and dried gelatine film must be
mentioned.
The film of the prepared print, in which the differences of swelling
necessary for the formation of the bromoil print are latent, develops
variations of relief when it is placed in water. Then the untanned
high lights absorb water, as already described, while the hardened
shadows do not absorb it. The result of this process is the formation of
those swellings, which, when they have attained a certain degree, are
characterized by the formation of a relief.
A definite degree of swelling corresponds to a definite temperature of
water. This swelling disappears again if the film is dried. _The gelatine
has, however, acquired the property of again attaining the same degree
of swelling when immersed in water at any time after drying, even if the
temperature of this water be a good deal lower._ A print, for example,
on which a certain relief has been produced in water at 35° C. (95° F.)
and which has given up this water again because of drying, again attains
the same relief if immersed in ordinary tap water at 10° C. (50° F.). If,
however, this print after drying is immersed in water at 40° C. (104°
F.), that is in hotter water than that first used, a still higher relief
is obtained, and again in a similar manner, after drying, it will attain
this higher relief when immersed in water at any lower temperature.
_The degree of swelling that is once attained can, therefore, so far
as the resistance of the gelatine film will permit, be increased, but
it cannot be reduced_, if the print as a whole is not subjected to a
tanning, as with formaldehyde, a process that is not easily controllable.
This peculiarity of gelatine makes it necessary to go to work carefully
in the formation of the relief, so as not to carry the latter too far.
If the work is begun on a too low relief this can be easily increased
to the necessary height, as will be shown later, absolutely without any
regard to any inking up that may have been done. _On the other hand, if
the formation of the relief has once been carried too far, as a rule the
print can not be used_, although reduction of the excessive swelling by a
tanning agent may be attempted.
The property of the gelatine film, just described, offers a further
convenience for the bromoil worker; for he can bring the bleached and
dried print to the necessary degree of relief in water of suitable
temperature, and, if he does not wish to work it up at once, it can be
dried and laid aside until needed. In working-up such prints he is then,
as a rule, relieved of the necessity of obtaining warm water.
_The question how far the swelling of the film has to go or in other
words what kind of a relief should exist, if any_, in order to obtain a
harmoniously graduated bromoil print, is extremely difficult to answer.
A few practical trials quickly give the ability to judge this correctly.
If a well-modulated negative is used, one in which the differences of
gradation between the high lights and the shadows are not too great, the
swollen gelatine film after drying should show a very delicate but still
noticeable relief; yet the high lights of the print should scarcely be
raised above the shadows, and should not show too marked a gloss.
The visibility of the relief is essentially determined by the character
of the print. The more contrasty the bromide print was, the more easily
are the different degrees of swelling made apparent by the formation of a
visible relief. A picture with sharp outlines and great contrasts, such
as an architectural study, easily gives a distinct relief visible in all
its details. Pictures with softer gradation, as, for instance, delicate
portraits, behave differently. One can not expect a striking relief in
such prints. If this should be forced by warming the water, the bromoil
print may easily attain an undesirable harshness. With portraits, one
should therefore be satisfied when the outline of the profile against
the background, the contours of the eyes and the mouth, are raised to
a barely visible extent from the gelatine base. At the same time very
dense parts, like a white collar, a lady’s light dress, lace, etc., may
show a very distinct relief, even when the sharper lines of the face
scarcely stand out in relief. Yet even in such cases the features can
be recognized by the different gloss of the high lights and shadows
under oblique observation. Naturally some attention must be paid here to
the particular views of the operator. If strong contrasts are desired,
greater differences of swelling must be used; if, on the other hand,
softly modulated effects are sought, distinct relief must be avoided. In
any case it is advisable not to attain this at once, but to get it as
needed during the working-up by the use of water gradually increasing in
temperature.
_It must be laid down as an axiom that the efficiency of a relief should
never be judged by the eye alone, but should always be carefully tested
out by inking-up with the brush._ The degree of swelling is correctly
estimated at the first attempt when, in inking-up, the picture appears
quite clearly after a little hopping, and this may happen if the
character of the image is right, even though no relief could be seen.
_The stronger the relief formed by warming the water, the more contrasty
the bromoil print will be._ Nevertheless there is a certain limit which
should not be overstepped. If the print is warmed in the water bath so
much that an excessive relief, which can almost be felt with the finger,
is formed, in which deeply cut lines alternate with highly glazed places
in relief, then the high lights are so saturated with water that under no
circumstances will they take ink; even the softest inks will not adhere
to them. Thus we obtain harsh highlights without details, while the
deeply sunken shadows literally fill up with ink and become sooty. If the
formation of the relief has been driven so far, it is not advisable to
treat the print with ink.
The forcing of the relief to the extreme possible limit is only justified
when working with a flat negative, in order to obtain as rich a gradation
as possible from a flat print. Also, this should not be done all at once
before the commencement of the inking-up, but effected gradually during
the work. Working in this way, extraordinarily successful results can
be obtained and the contrast of the bromoil print can be made far more
rich than that of the original bromide print. The limit lies only in the
resisting power of the gelatine film and the flatter the bromide print
was the sooner this is reached.
The upper limit of temperature permissible for the water can hardly be
defined; it depends entirely on the hardness of the gelatine film. It may
happen that it is necessary gradually to go almost to the boiling point.
Films that are hardened right through will withstand even boiling water
without forming a relief.
If, in warming the print, the melting point of the gelatine is
approached, those parts which are but slightly tanned, such as the high
lights, and especially any unexposed edges, begin to show a granular
structure, and finally, when the heating is carried further, to melt.
_In the development of the relief great care should be taken that no
part of the print remains dry_, and, if the film is placed face down,
air bubbles should be avoided. If the print is placed face up in the
dish, no part of it should project above the water, as it will then not
absorb enough water; if the swelling has already taken place and a part
of the film projects above the water (and this frequently happens, as
the print, which at first lies on the bottom of the dish, after some
time rises to the surface), the relief of the exposed parts goes down
after some time, since the water evaporates from them into the air. Such
insufficiently swollen parts, or those which have dried out, behave
exactly as though they had been tanned more than the other parts of the
surface. They have been able to absorb little or no water, or have lost
the absorbed water by evaporation. They therefore take the ink, like the
tanned shadows, far more readily than they would if they had retained
the right amount of water, and far more ink adheres to them than should
be the case and than adheres to the correctly swollen parts of the film.
Thus patches of different form and size are formed at these places by
the stronger adherence of the ink. Yet by renewed soaking of the print
in the water these neglected places may be easily brought anew to the
correct degree of swelling, and as far as concerns small spots caused by
air bells, can be easily corrected. If larger patches of the film are
insufficiently swollen, after the application of the ink they are usually
much darker than the rest of the surface, and in such cases it is not
always easy to obtain again the necessary evenness of the ink; it is then
often necessary to ink up the whole print much more strongly than was
originally planned, or to remove the whole film of ink.
Besides the warm water bath there is also another means at our command
to produce the differences of swelling. This is the use of _ammonia_.
A. & L. Lumière and Seyewetz, in a treatise published in 1913, on the
resistance of gelatine to alkalis, found that cold solutions of ammonia
did not attack gelatine but caused it to swell more.
If a bleached print is immersed in an aqueous one per cent solution of
ammonia, the film attains in a very short time _the highest degree of
swelling of which it is capable_, without the gelatine in the high lights
being softened or damaged. The estimation of the height of the relief,
which is so important for the successful carrying out of the inking, is
scarcely possible with the ammonia bath, as it is extremely difficult
to gauge its action. Therefore, it should only be used in those cases
in which the highest swelling is absolutely necessary, as for instance,
when using papers which have been strongly hardened in the manufacture,
or with prints with very poor contrasts. A further application is with
the transfer process, in which on the one hand it permits of the use of
very soft inks and on the other hand enables one to keep the gelatine
very resistant. Full details on the transfer of bromoil prints will be
found in a later chapter. In very extreme cases, one may try to combine
the action of the warm water and the ammonia bath, and use a warm ammonia
bath. The ½ to 3 per cent solution of sodium carbonate recommended by E.
Guttmann acts even more energetically than the ammonia solution.
As is obvious from the foregoing remarks, it will be as well to work
usually with water baths and leave the ammonia bath for a last resource,
the more so as in the swelling of prints in this bath certain troublesome
phenomena may appear, which do not occur when using the water baths.
Sometimes the bleached image reappears in the ammonia bath in a brown
color; sometimes small white spots appear on the prints which will
not take the ink and which, as can be determined by examining them by
transmitted light, also exist in the substance of the paper; finally the
gelatine film sometimes swells all over, so that the ink is not taken
up anywhere. Prints which are failures in consequence of the use of the
ammonia bath, should be dried and can be again treated in a warm water
bath.
THE UTENSILS.—For the application of the ink the following are required:
_Brushes._—A best quality oil-printing brush with very elastic hairs
cut on the slant, the so-called stag’s-foot brush, should be used. To
apply the ink, a brush should be used with a working surface of from 1½
to 2½ cm (⅝ to 1¼ in.) diameter; by diameter is meant the length of the
longer axis of the elliptical surface produced by the slanting cut of
the brush. For working-up very small surfaces or for placing accents of
color, a brush of about ½ cm (³⁄₁₆ in.) measurement should be used. In
certain cases still smaller brushes may be useful. Such brushes are only
used for working up details; they are only aids for special work. For the
application of the ink generally, only the larger brushes should be used.
It is far more difficult to apply the ink evenly with small brushes than
with the larger ones, so that their use may cause needless discouragement.
The application of the ink is effected by placing the whole working
surface of the brush charged with ink on the print, and then slowly
lifting it up; this results in a deposition of ink corresponding to
the working surface of the brush used. The smaller the brush the more
often it must be applied, and therefore, the greater the probability
of irregular inking, especially in those parts where the brush marks
overlap. Also small brushes are handled less conveniently than larger
ones and smear easily. The first thing to do in inking a bromoil is to
obtain a good, even, thin film over the whole surface, to get a general
impression of the whole effect. Only then is one in a position to judge
how the tone values should be varied. The use of too small a brush unduly
protracts this first operation and makes it difficult.
The brushes should be elastic but not too soft. Too soft brushes smear,
that is to say, they deposit the ink in a thicker layer at their edges
than in the middle and produce elliptical rings of ink, which must always
be evened out by hopping.
In determining the size of the brush, the size of the bromoil print must
be taken into account. Generally it is easier to work with brushes of
from 1½ to 2½ cm (⅝ to 1¼ in.) in diameter. For large sizes up to 30
× 40 cm (12 × 16 in.) brushes of even 4 or 5 cm (1½ or 2 in.) may be
used. Such brushes are not cheap, but are practically indestructible, if
they are properly cleaned every time after use. The brushes are sold in
tubular paper cases; these latter should be preserved and the brushes,
after cleaning, put back into them, so that they are covered and the
hairs do not get ruffled.
In order to preserve the brushes and keep them in good working order,
they must be cleaned as soon as the work is finished, otherwise the ink
left in them sets and makes the hairs brittle.
Brushes of long swine bristles with cut ends may also be used; with these
especially, clean prints are quickly attained. They are superior to hair
brushes of poor grade.
_The cleaning of the brushes_ is best effected as follows: Pour
into a deep dish a _readily volatile_ fat solvent, such as benzol,
trichlorethylene, carbon tetrachloride (carbona), etc.; but not
turpentine, for if this be used the brushes cannot be used sometimes for
days. Dip the brush into the liquid and press out the solvent on the
edges of the dish, and stroke the brush vigorously on a piece of lintless
linen, which should be used for this purpose only. The solvent can be
used, ignoring the opacity which it soon assumes, as long as it will
dissolve the ink. Only the hairs of the brush should be dipped in the
solvent, but not the binding, as in some cases the cement with which they
are fastened may be attacked.
_The Inks._—Theoretically, any ink prepared with a fatty medium is
suitable for bromoil printing. In order to give satisfactory results, the
inks must satisfy two conditions: they must have the correct consistency
and their medium must be soluble in benzol. As regards the consistency
of the ink it should be noted that the prepared film in its swollen
condition, that is when the lights are saturated with water, absolutely
repels greasy inks only when this swelling attains the highest possible
degree; a case which one seldom needs and which will usually have to be
avoided. If this swelling is not carried to the limit, the high lights,
in spite of the water they hold, will take up the greasy ink, yet usually
only when the ink is very soft. _The swollen high lights thus repel ink
of thicker consistency, while they take the softer inks more easily in
proportion as they become thinner._ That the tanned shadows also take
hard ink is natural, for they do not contain, or contain only to a very
small extent, the water which repels the ink. From these considerations
it follows that in many cases satisfactory results cannot be obtained by
using ink of only one consistency.
_The hard or heavy ink_ should have about the consistency of table
butter, and it should be possible to spread it into an even smooth film
on a glass plate with light pressure. _The soft or light ink_ should have
about the thickness of honey and should spread under the knife without
noticeable pressure.
_Collotype or copper-plate printing inks_ of various makes are frequently
usable. As a rule, however, they must be tested as to their usefulness
for our process; their consistency is frequently too hard, and sometimes
they are not taken up by the film or cannot be distributed well, even
when they are considerable diluted with linseed oil varnish, in spite of
an apparently correct consistency.
The nature of the ink is not only influenced by the greasy substance used
as a medium, but also by the material of the coloring matter itself. This
is why many inks, in spite of their apparent softness, work tenaciously
or “short,” while sometimes inks of hard consistency smear.
If occasionally the dilution of an ink of too hard consistency appears
necessary, this is best effected with linseed oil varnish, which,
however, should not contain any driers. If the work has been begun with a
stiff ink of a certain shade and it is desired to retain this tone to the
end, it is advisable not to use a thin ink for dilution, but to thin down
the stiff ink with varnish.
_Inks of too hard nature_ are not practicable. Such were necessary in
the oil-printing process. In the bromoil process, which is much less
sensitive to the consistency of the ink, their use merely means a
needless loss of time. An ink of correct consistency is easily taken up
and produces quick drawing without smearing, while too hard inks are
difficult to apply and soon refuse to take if they are not diluted.
It is extremely simple and advantageous to prepare the inks oneself, as
outlined by E. Guttmann in Chapter VIII, p. 177. The process recommended
by him is to place the powdered colors on a matt glass plate and rub
up with varnish by means of a muller or pestle. This procedure is
considerably facilitated, if, according to my suggestion, a few drops
of a readily volatile oil-solvent be added. The ink is thus immediately
liquefied and can be quickly and perfectly rubbed up. The solvent
evaporates during the grinding, which is much easier than in the old way,
and the ink again acquires the desired character without suffering in any
way.
_As a palette for the ink_ the best thing is a piece of waxed or
parchment paper, fastened on a white support, such as a card. Such a
palette has the advantage that after use it can be discarded without
cleaning. Moreover the color value of the ink can be fairly easily
determined on it. If necessary old negatives, or other glass, may be used
as a palette, and their use also makes cleaning unnecessary, which is an
unpleasant and messy job.
A small quantity of ink should be taken and distributed as thinly and
evenly as possible on the palette. A thick layer is not convenient, as
then the brush takes up too much ink and too much is deposited at a time
on the bromoil print. The film of ink should show as smooth and uniform
a surface as possible; thicker ridges should be avoided, because the
brush is thus more strongly inked in spots and therefore transfers
the ink unevenly to the print. The distributed ink should be perfectly
homogeneous and flexible. A thin layer of ink sets to a skin on its
surface after a short time and then cannot be used.
This setting also takes place in the body of the ink and becomes evident
by the formation of a delicate skin or hard crumbly particles on the
surface of the ink. These must always be removed; such hardened inks can
only with difficulty be distributed on the palette. Finally it should be
mentioned that hard inks may be slightly softened by warming.
THE SUPPORT.—A stout glass plate or drawing board should be used as a
support, and inclined at an angle of about 30 degrees by propping up at
the top; _a damp and elastic pad_ must be placed on the glass or board.
_This pad is not for the purpose of keeping the print damp during the
working-up, as is usually stated_; on the one hand this is superfluous
in view of the possibility of repeated soaking, which is to be described
later, and on the other hand it would not produce the desired result. It
is erroneous to suppose that the water which passes from the damp support
to the paper side can equalize the loss of water which the film suffers
by evaporation from its surface. The pad should, therefore, only be so
damp that the bromoil print adheres firmly to it, when under the brush.
The pad should absorb and hold moisture; but this should not be imparted
to the brush when it touches the pad in working-up the edges, otherwise
water will be carried on to the print and cause spots. _For this reason
damp blotting paper or filter papers should be absolutely rejected for
the pad._ If such papers are used for the damp pad, the brush, which in
working the edges must inevitably touch them, will not only take up water
but also the paper fibers and, transferring them to the print, cause
trouble. Moreover, sheets of paper in a damp state are difficult to lay
smooth and are scarcely usable.
The best material for the pad is the _copying sheets_ used for copying
books, which consist of two layers of linen with an intermediate film of
rubber. Such sheets have the advantage that when damp they always remain
flat and smooth. A damp piece of linen, doubled and smoothed out, is also
simple and certain. The pad must lie absolutely flat, because any ridges
become most unpleasantly visible in inking-up, particularly with thin
papers, as the brush always slips from the highest parts of the ridges
and causes inequalities in the print.
REMOVAL OF THE WATER FROM THE SURFACE OF THE PRINT.—After the prepared
print is removed from the water and laid on the pad, the water adherent
to its surface must be removed. This is best effected in the following
way: Take a large, absorbent, lintless cloth, spread it smoothly over
the print, and press it gently with the flat of the hand. By repeating
this, the water is easily removed without endangering the film; whether
the drying is complete can be judged by _examining it obliquely. The
freedom of the cloth, used for drying the print, from fluff and lint is
of great importance._ If the cloth gives up fibers to the surface of the
print, these cannot be seen at first. In inking-up, innumerable minute
dark spots and lines appear on the film, as the deposited fibers take
the ink very strongly and thus suddenly become visible. It is frequently
erroneously assumed that such troublesome defects come from the brush.
This is seldom the case; on close examination these fibers will be seen
to be particles of the textile material. When possible, linen that has
been frequently washed should be used for the drying.
When the water is to be removed from a print that has already been inked
and again soaked, care should be taken that the cloth is freed from any
folds by damping and subsequent drying, for such folds can, when pressed
on the print, damage the film of ink. Although this is not of material
importance, as such faults can be easily evened out by hopping, yet
these small precautions avoid unnecessary trouble. Sidewise or wiping
movements of the cloth should be carefully avoided, especially if the
print has already been inked, because the ink is unnecessarily smeared by
the wiping. After removal of the cloth one should make sure by examining
the print obliquely that the water has been completely removed from the
surface.
It is advisable to keep several cloths ready for drying off the film, for
this will have to be done fairly frequently during the work. _Care should
be taken to remove most carefully every trace of water; water which is
picked up by the brush causes spots_, for the drops of water in the brush
keep the ink away from the points of contact. In such cases it will be
seen that white spots make their appearance in different parts of the
print, continuously shifting their position during the work. By perfect
drying off, these phenomena, which are in any case not necessarily
important as regards the final result, can be avoided. In drying off a
print already inked-up, the cloth will as a rule remove some ink from
the surface; such cloths should not be used again until they have been
washed, because they may transfer ink to a place where it is not wanted.
THE BRUSH WORK.—The prepared print, lying flat on the pad, and with its
surface freed from adherent water, should now be inked up.
Before beginning the application of the ink a little stiff ink, at least
as large as the working surface of the brush, should be placed in a
corner of the palette. This should be spread out flat, thin and free from
ridges; then the knife should be wiped and a little soft ink spread in
another place.
The brush should now be pressed down on the _hard ink_ already
distributed on the glass plate, and the ink dabbed very carefully from
the brush on a clean place of the palette. _One should never go with
the brush direct from the ink itself to the print, as this will form a
spot which it is difficult to work out. It is of the greatest importance
always to work with a brush that has been well dabbed out and in which
the ink is evenly distributed._ If the brush has not been sufficiently
dabbed out it leaves on the print a quantity of small, much darker and
usually linear particles of ink, which cannot be distributed or are only
removable with difficulty. Such spots must then as a rule be removed by
the method described on page 72.
The whole brush technique is based on the following principle: if the
brush charged with ink is placed on the print and allowed to remain there
for a moment, and then _slowly_ lifted up, the ink remains on the image.
If it is set down sharply and _quickly_ lifted (the so-called “hopping”),
it removes ink. In the first inking-up of a print, the swelling of
which has been correctly carried out, the application of the ink may be
effected by a gentle dabbing. A very thin film of ink is thus produced
and almost simultaneously correctly distributed.
The brush should always be held by the extreme end between two fingers,
never by the middle or near the hairs. _The more lightly and more
delicately the brush is managed the better it works._
It is best to begin the work at some characteristic place of the picture,
which is well known to the worker; the ink should first be spread as
delicately and evenly as possible on a small spot, avoiding, as far as
possible, going over the same place twice with fresh ink. When the place
selected has been covered with a light film of ink, the surface should
be hopped over with light movements, when, with correct preparation of
the print, the outlines will soon appear. _A bromoil print correctly
prepared_, and with swelling suitable to the ink used, _is easily
recognizable by the fact that the image appears delicately but distinctly
under the very first strokes of the brush_. If this does not happen even
after some time, either the degree of swelling of the print is too low
or there is some fault in the preparation of the print, such as, for
instance, unsuitable paper, a poor bromide print, errors in bleaching,
etc. The longer the hopping continues, the more distinct the details
should become. Then the application of the ink should be continued in
places adjacent to those already worked up, until finally the whole
surface of the print has been evenly gone over with ink and the image is
visible in all its details, although still very thin and delicate. It is
advisable to use a rough print from the negative as a guide.
_Beginners usually make the mistake of jumping from one spot to another
without filling up the intervening parts._ This makes the work more
difficult. Inking up should be carried out continuously by passing from
those places already worked on to those not inked up. If it is noticed
that the places which were first inked up appear too pale compared to
their surroundings, since they have still too little ink, they should
be inked up more strongly. Too dark spots should be evened out with the
brush by removing the excess of ink and depositing it on the less inked
parts. The amount of ink used on the print is very small; that which is
first taken up by the brush lasts for a long time. It is not necessary to
have frequent recourse to the ink spread on the palette by the knife, but
is much better to take up, as long as possible, fresh ink from the spot
on the palette on which the brush was dabbed.
_On the other hand, however, every application of the brush to the print
should actually deposit some ink on the print._ If those parts touched by
the brush do not increase in intensity, _it must be determined whether
the dark places on the palette from which ink is supposed to be taken,
are actually giving up ink_; for if the film of ink remaining on the
palette is too thin, fresh ink must be deposited and distributed on it by
the brush.
Care should be taken not to overload the brush with ink, for then
the hairs stick together, distribute the ink badly on the print and,
moreover, frequently leave large coherent particles of ink on the film,
thus causing spots. As the brush is cut on the slant, it may happen that
in dabbing out the brush on the palette and in the application of the
ink to the print, the front and longer part of the brush is used more
strongly. Then the ink collects at the back edge of the brush and causes
spots when the brush is used more vigorously.
In many cases it is possible to complete the print with the hard ink
alone. _If it is noticed that the hard ink does not take well on the
print and is removed again in lifting the brush_, its consistency is too
stiff for the work. One should not then continue to use it, but should
_soften the ink_ in the following manner: First place the brush in the
hard ink and dab it out well in another place on the palette. Now dip the
ends of the brush hairs carefully and very lightly into the soft ink and
dab out the very small quantity of the soft ink taken up by the brush on
the same spot, on which the hard ink has been previously distributed.
There is thus formed on the palette as well as in the brush a mixture
of the two inks. Now try carefully whether the now softened ink adheres
well to the print, by placing the brush lightly on a light place of the
print. If it leaves behind a _light_ trace of ink without any trouble,
the consistency is correct; but if this does not happen, the ink must be
diluted again in the same way with the soft ink. If on the other hand
the brush leaves behind a _strong_ trace of ink from a light touch, the
ink is too soft and requires the addition of some hard ink. _It is not
advisable to mix the soft and hard inks on the palette with the knife, as
it is very difficult to strike the right consistency in this way._
This applies to all mixtures and dilutions of the ink which may be
necessary in the course of the work, as in strengthening a colored ink
with black, or in the preparation of any desired tint by admixture of
different inks, and finally in softening inks with varnish. In all these
cases mixing of the inks on the palette with the knife puts too much ink
into use; also, as long as the ink is on the palette, one cannot estimate
with the necessary exactitude either the tint or the consistency. The
correct procedure is rather first to go with the brush to the first
color and distribute this on a clean place, then set the same brush in
the second color and make the mixture on the palette by dabbing. Then the
mixture thus obtained should be tested as to its shade of consistency
by gentle application to the print, and more of one or the other ink
added in the same way with the brush. It should be noted that inks of
a soft consistency go a very long way; the whole surface of the brush
should never be dipped into such inks, but only the point of the brush.
Softening of the inks with varnish should be effected in the same way.
When the first inking up is finished, the addition of ink of the same
consistency is continued until the print is completed or will no longer
take ink, which, as has already been pointed out, is known by the fact
that the newly applied ink no longer adheres, but that the brush removes
it from the print. Then one proceeds to a further dilution of the ink
by taking more soft ink with the brush and adding it to that already
mixed, and continues the work. The use of the unmixed soft ink is not
even necessary in many cases. If, however, it proves to be necessary, it
should be used, but with care, for a brush stroke which puts too much
soft ink on any part of the print, especially in the shadows, causes a
patch. _The beginner will work most easily and successfully if he always
keeps the applications of ink as delicate as possible and obtains depth
only by a repeated and even coating of ink, fully distributed every
time._ If a place should still turn out to be too dark, one can try
removing the excess of ink, if it be a hard one, with a clean brush. If
a dark patch is formed by too vigorous application of a mixed or even a
soft ink, another brush should be dipped into the hard ink, dabbed out,
and the spot removed with this brush. Moreover, such places can as a rule
be easily rectified after the second soaking of the print, which will
be described presently. If the fault cannot be removed in this way, the
ink must be partially or entirely removed, according to the instructions
in Chapter III, page 73, and the work begun anew. This should be done
without hesitation by the learner if the application of the ink does not
succeed as he desires; the prepared print can be used for practice like a
school slate by washing it off after each attempt with a solvent of the
greasy medium.
For the application and the hopping off of the ink for large areas of the
print one should _always use the whole working surface of the brush_.
Smaller surfaces or outlines should be worked up with the front edge of
the slantingly-cut brush; in laying on the ink one should never continue
with the point, because this bends and gives unpleasantly sharply defined
ink edges. _In order to cover a place with ink very thoroughly, one
should hold the brush firmly, give it a slight twist and then raise it
up straight and slowly._ If it is desired to coat a whole print evenly
with ink, it should be applied in stripes over the whole print, the brush
being pushed forward and not necessarily completely lifted up from the
surface. The brush is pressed down firmly, the pressure relaxed a little,
the brush moved forward half its width, then pressed again, and so on. In
this way with a little experience there may be produced perfectly even
ink stripes which bring out the outlines of the image and which are made
close together until the whole print has been gone over, when one begins
with the hopping. With papers with marked structure these stripes are
best made in the direction of the structure and not at right angles.
_Especial care should always be taken that the shadows of the print,
which take the ink most easily, are not too strongly inked up, and one
should try by light hopping to bring out all the desired details at the
very first application of the ink._ When the shadows have once taken too
much ink, it is not easy to clear them up by brush work alone. The inking
up of large deep shadows must always, therefore, be very carefully done.
Such parts of the picture are the most strongly tanned and therefore take
the ink very readily and hold it very tenaciously. They should therefore
never be touched with a brush freshly charged with ink, but one should
work on the heavier shadows only when the brush has given up the greater
part of its ink to the less sensitive parts of the image. Even then it
always contains enough ink for the darker parts of the print. The first
application of ink in the shadows, especially, ought never to be heavy
and cannot be kept too delicate. When the desired details in the shadows
appear to be well defined, they should then be strengthened. But even
this should not be effected by a single thick coating of ink, but by
successive additions of thin ink films and hopping after each.
Especial emphasis must be laid on the statement that _all details_, which
it is desired to have in the finished print, _must be brought out by the
first application of the ink_. If parts of the image are strongly inked
up before the desired details have appeared, it is difficult to develop
these later. On the other hand, detail, which has been brought out in the
first inking, cannot be suppressed by any further skilful application of
ink, but only strengthened.
These phenomena can on the other hand be successfully used to prevent the
appearance of undesirable details in the picture. If for artistic reasons
one desires to suppress detail and work flatly, the parts in question
should be inked up from the start more strongly and evenly, and the
hopping be either entirely omitted or stopped before the details which
are to be omitted are brought out.
For beginners especially, it is useful in applying the ink, as well as
in hopping, to lift the brush after every few strokes and examine the
results obtained, so as to decide on further procedure.
One should accustom oneself to examine the print _from time to time
at a certain distance_, while it is being worked on; for the correct
impression as to whether the tonal values are correctly chosen, can
be gained only at a greater distance; it is then seen more easily and
clearly whether or not individual parts of the print carry too much or
too little ink.
Particular parts of the print, which one wishes to have _more contrasty_,
should be gone over after the hopping with _a wiping motion of the
brush_; the ink is thus removed from the raised parts of the relief. If
one goes too far in this, the inking can be done over again in the usual
way.
If it is desired to free a brush from the soft ink, it should be dipped
into hard ink specially spread on the palette for this purpose, and
dabbed out well on a clean place, and this operation repeated two or
three times, using each time another part of the palette. At the end of
this manipulation the brush will practically no longer contain anything
but hard ink.
When one has once learnt the initial steps of brush technique, in the
course of time one fails to notice the difference between the laying on
and the hopping off of the ink. _The hand in time acquires an instinctive
handling of the brush, which takes care at once of both the application
and the distribution of the ink_; if the proper relation between the
consistency of the ink and the degree of swelling of the gelatine has
been hit upon, a simplified handling of the brush comes of itself,
because then the application of the ink is especially easy.
When, with papers of rough surface, the grain of the paper remains white
in the shadows, in spite of hopping, such places should be treated by
going over them with the inked brush with light pressure _with a rotary
motion_.
_Practice teaches that there is always a definite consistency of ink
which corresponds to a definite degree of swelling_ and with this the
print may be executed from start to finish. If the operator has learnt
by experience what ink consistency corresponds to the existing swelling
of the film, he will prepare his ink of the suitable consistency, and is
then in a position to carry out the work uninterruptedly without any new
mixing of the ink.
It is a little difficult for the tyro to answer the question as to _when
the application of the ink should be stopped_, that is to say, when the
print may be looked upon as finished. There is frequently a temptation
to consider the print finished when it is very delicate yet completely
visible in all its details. The beginner often lacks the courage to apply
more ink at this stage; he usually believes also that the print will
take no more ink, because, as has been mentioned above, the part of the
palette from which he has hitherto taken the ink, gives up no more. Such
prints, which recall sketchy pencil drawings, deceive one during the
work, but only satisfy later if this particular technique is suited to
the character of the picture, which is certainly not always the case.
One must therefore carefully consider during the work whether one should
actually stop.
The second danger lies in the opposite direction, and is due to the fact
that, led on by the constantly increasing vigor of the image, _one cannot
rightly decide when to stop_. The danger here is that one is tempted by
the vigor of some part of the picture to make the other parts also as
strong in color, until by such continued action the print is immersed in
the deepest gloom, which becomes still more gloomy after defatting the
finished print. Such excess must be avoided as a rule. Experience and
taste soon teach one to hit the happy mean.
The first, delicate and general application of ink, which may be
considered as a guide print, is in many cases somewhat wearisome,
especially when the picture has large areas of rich, deep shadows. With
correct preliminary treatment of the print there are no real difficulties
in the preparation of such a guide print. Yet the work, especially with
large sizes, is really time-consuming and also offers, when considered
from the artistic standpoint, but little interest, since the actual
creative work of the operator only begins after the guide print is
finished; only then is he in a position to actually give expression to
his artistic feelings by suitable inking of the different parts.
Since, therefore, the work in the preparation of the guide print is
actually quite mechanical, it is natural to make use of any means which
enables one to facilitate and hasten this work.
For this there may be used, but only by the expert worker, a method based
on the following considerations:
If an ink of suitable consistency is dissolved in a suitable solvent,
such as benzol, carbon tetrachloride, trichlorethylene, etc., the
pigment is very evenly disseminated in this solvent. If the latter again
evaporates, the ink deposits in an even coating, unchanged in its nature.
It is therefore, possible, in the first application of the ink, to use
such a solvent on the print and by its aid the wearisome mechanical work
of the first inking may be rapidly and easily carried out.
In practice the method of procedure is as follows: there is first
produced, on the print which is to be worked up, a relief which is
vigorous enough to sufficiently develop all the detail in the shadows.
An ink which is fairly stiff for this degree of swelling is chosen; the
brush is first dipped in the solvent and then into the ink, which has
been thinly spread on the palette. After a few dabbings on the palette
the ink solution with which the brush is charged is spread on the print
with a hopping motion and distributed with the same brush as evenly
as possible. If the distribution becomes difficult in consequence of
evaporation of the solvent, the brush should be again dipped in the
solvent, and then the distribution can be easily completed. The film of
ink thus obtained should be fairly thin, but must not be quite even.
After the complete evaporation of the solvent, the ink is worked up with
a clean brush, with which the guide print can be finished without trouble
and in the briefest time.
There are also other variations of this method of the application of
dissolved inks. For instance, one may first apply some ink with the
brush to the print and then distribute it with a second brush dipped in
the solvent; one may also prepare a solution of the ink in a dish and
paint it on the picture, or bathe the whole print in a solution of the
ink. All these variants, especially the last two, have, however, certain
disadvantages, so that the procedure first outlined is to be preferred.
After the guide print is prepared in this way, the further application of
the ink is carried out in the normal manner.
The solvent is most conveniently chosen so that it is not too volatile,
as for instance heavy benzol. But it ought not to contain any oil. When
placed on the surface of the hand, it should evaporate fairly slowly, but
without leaving any trace of grease.
Certain failures, which sometimes appear in this process, must be
mentioned. If the film of ink is too thin, it can be repeated without
further trouble in the same way, with rather more ink. If, on the other
hand, too much ink is applied, a complete image is immediately formed
without any possibility of the shadows being worked up. In this case the
ink must be again removed by the solvent. If individual parts of the
picture are too dark, from too much ink, it is sufficient to go over
these parts with a brush dipped in the solvent, in order to clear them up.
If, after evaporation of the solvent, great irregularities in the
distribution of the ink are seen, as for instance, spots and streaks
which cannot be easily worked out, the print should again be placed
in water; after drying off, the evening-up may be carried out without
difficulty.
If in hopping with the second clean brush the image does not appear at
once without trouble, either the relief was too low, or the ink too soft,
or the solvent contained oil.
The ink can obviously be placed on the bromoil print not only with the
brush but with any other suitable ink carrier, such as _rollers_. Yet by
this the process is rendered _more mechanical_ and deprived of all those
great advantages, which distinguish it from all other printing methods.
_Especially, the possibility of local treatment is mostly lost_; the
unlimited command of the tonal values and the structure of the ink can
only be guaranteed by the use of the brush. The only offset to this loss
is a gain in speed. Agility, however, is not sought after in artistic
labors. If one wants to prepare a lot of prints quickly, it is better
to use the bromide process, which is especially suitable for such a
task, and thus save the trouble of the bleaching and the other processes
necessary in making bromoil prints.
RESOAKING OF THE PRINT DURING THE WORKING-UP.—_Resoaking the print during
the inking up, without regard to the existent film of ink, is one of the
most important aids in the bromoil process._
This procedure is based on the following considerations: It has already
been pointed out that the prepared gelatine film possesses the property
of again assuming after drying the same degree of relief which was
imparted to it by the warm water bath. When a swollen print is taken
out of the water and placed on the pad for working up, evaporation
immediately begins at the surface of the film; the gelatine, therefore,
continuously gives up water to the surrounding air during the work,
and more quickly in proportion as the air is drier and warmer. As has
already been mentioned, the damp pad does not alter this, since the
supply of water from the pad through the paper is not sufficient to
restore the water content of the film. Therefore, while one inks up one
part of the print, all other parts gradually lose their water; and since
it is this water which renders the gelatine, after its tanning, capable
of repelling or taking the greasy ink, the work gradually becomes more
and more difficult. The gelatine film, which feels smooth when the film
is removed from the water, especially in the high lights and any exposed
margins, becomes gradually leathery. It may still take ink, but the
distribution of this, and especially the development of the drawing and
the details, become more and more difficult.
_If, however, the print, which is partly or entirely inked up, is again
placed in water and this time in cold water, the gelatine film very
rapidly absorbs this and again attains the same degree of relief that
it had at first._ Sometimes it appears as though a marked clearing up
of the image takes place in the water; the high lights become cleaner,
and many details appear in the shadows which were not visible during the
working-up. On the other hand, with some inks the picture appears to
become weaker under the water. This, however, is only an illusion and is
of no importance, as in drying, or in again going over the picture with
the brush, the image again attains the previous depth and color and still
greater clearness.
Here also, one must take care that the print is _completely immersed_ and
that no air bells adhere to the film, since those places to which the
water does not have access do not reswell, and on further work may give
rise to spots. In removing the print from the water the inked-up surface
should not be touched with the fingers, or finger prints will remain in
the ink. The print should therefore be taken hold of by the edges.
While the print is soaking in the water, the bringing out of the details,
especially in the shadows, may be facilitated by stroking those parts
with the tip of the finger or a swab of absorbent cotton. In the same way
dirt which has collected on the surface during the work may be removed.
In the latter case one may also use more vigorous friction, even though
the ink film is thus removed, since the removal of the troublesome
particles is more important than saving the thin film of ink, which can
be easily renewed.
The print is then removed from the water, placed on the pad, and dried as
previously by spreading over and pressing down a lintless cloth, although
because of the film of ink any wiping action should be avoided. Then when
the brush work is resumed, it can be completed in an extraordinarily easy
manner.
It should be specially noted that the print must be _worked up after this
second soaking with the same brush as before, which need not be recharged
with ink_. Only after the print has been hopped in this way, should fresh
ink be applied.
During the work, the bromoil print, as a rule, will scarcely retain the
necessary degree of dampness longer than a quarter of an hour, and not
this long in dry and warm weather.
_The resoaking of the print should be undertaken without hesitation as
often as any difficulty in the distribution of the ink is met with; for
this saves a great part of the brush work_, and almost automatically
brings out contrasts and details. Especially while learning the process
and later with more difficult prints, the work is most conveniently
divided as follows: first application of the ink and distribution
by hopping, as long as it is easy; resoaking the print; drying off
and hopping anew with the brush not freshly charged with ink; second
application of the ink and hopping of the ink now applied; another
soaking, and so on. The operation may be repeated as often as desired
without the film taking any harm.
Because of the possibility of always bringing the print to the correct
degree of relief during the brush work by means of resoaking, _there is
absolutely no limit to the size of the bromoil print_. One can simply
finish a part of a print of any desired size and then, after another
soaking, go on to the next part and so on until the whole print is inked.
If the relief of the film corresponds to the desires of the operator,
the bromoil print may be finished completely in this way. _If it is
seen that the relief is not sufficient to give the desired modeling and
contrast, the resoaking may be effected with warmer water than was used
at first._ Yet, until the worker has completely mastered the process,
this should be done carefully and the temperature of the water gradually
raised by adding hot water, in steps of not more than five degrees, until
the requisite relief is attained. The use of a _thermometer_ is here
absolutely essential, for the estimation of the temperature of the water
by the hand is quite unreliable and may lead to the greatest errors. This
applies to all water baths used in the bromoil process. At this point it
should be noted that a print, which on account of its characteristics has
to be placed at the beginning in very hot water to attain the necessary
relief, is usually covered with very tiny air bells, which can easily
be overlooked; they must be removed by wiping under water so as to avoid
troublesome spots.
If the relief of the whole print is satisfactory, but, because of the
character of the negative, a few places in the deep shadows do not show
the necessary details, the desired shadow detail might possibly be
attained by increasing the whole relief, yet at the same time the relief
in the rest of the image would be carried too far. In such cases, the
places which should be relatively more swollen can be separately more
highly swollen while the rest of the surface of the print retains the
original relief, by pressing on them a cloth soaked in warm water or a
suitably formed swab of absorbent cotton. A still stronger effect is
obtained when such places are painted with a water-color brush charged
with a one per cent solution of ammonia, either on the film or, after
previously marking the outlines, on the back.
When the relief of the gelatine has been increased by soaking in water
which is warmer than that used for the first bath, certain precautions
must be observed in removing it from the water. It frequently happens,
when using certain inks, that _the water which runs from the film causes
streaks and spots_, and that evening these out is at least troublesome
and frequently very difficult. This action, which does not occur when
resoaking in a bath of the same or a lower temperature, is explained
by the fact that the greasy medium of the ink is liquefied by the high
temperature of the water, and runs down irregularly or mixes with the
water and is carried off by it. There are thus formed on the film of ink
marks which show the form of the streams of water which have run off.
Such troubles may be avoided by bringing the support close to the dish
in which the print is soaked, lifting the print out of the water as far
as possible in a horizontal position and placing it in the same position
on the support, and immediately spreading the previously dried cloth
over it and carefully drying. By observing this precaution, the running
off of the water from the film, which is the cause of this difficulty,
is prevented. Any traces left by the cloth, used for drying off, can be
easily evened out again by the brush.
By making use of this soaking of the print during the work, the bromoil
printer _is absolutely unlimited in the time used for his work and is not
driven by any necessity for haste_. He can continue his work in peace and
without hurry, and devote himself to any particular part of his picture
at will, without being afraid that other parts will meanwhile lose their
capacity for being worked up.
THE REMOVAL OF THE INK FROM THE SURFACE.—If, in the application of the
ink, a fault occurs, which for any reason cannot be corrected with the
brush, or if one sees in the course of the work that the ink film is
not satisfactory in tonal values or shading, the print would have to be
discarded, if it were not possible to remove the ink without damage to
the film. This is feasible, however, without any special difficulty; one
need not, therefore, throw away such a print, but after removal of the
ink can again ink it up, but this time with avoidance of the previous
fault.
_If there are only small faulty places, the ink may be removed from the
print as it lies on the pad, as follows_:
Cut a small piece of transparent, waxed paper, or, lacking this, of thin
smooth white paper of approximately the shape of the overinked spot, but
slightly larger, and place it on the faulty spot, turning up a little
corner so as to be able to lift the paper again. Then rub with the finger
tip carefully and pull off. The ink is thus removed from the bromoil
print and transferred to the paper. If the removal is not complete, the
operation is repeated with a second piece of waxed paper. If very small
places, as, for instance, the eyes of a portrait, have to be dealt with,
the rubbing should be done with a round stick, such as a penholder.
_By inking again, the part that has been thus removed may be replaced
without any trace of a correction._
If the whole film of ink is to be removed from a bromoil print, _a soft
dry cloth or better still a swab of absorbent cotton should be soaked in
benzol or other solvent, and the picture washed with it_. The medium of
the ink is dissolved by the benzol and the ink taken up by the wiping
cloth.
Every stroke must be made with a clean portion of the swab, which must
frequently be soaked again with benzol, otherwise the ink dissolved by
the benzol and taken up by the swab will be again put down on the paper.
If, after washing with benzol some traces of ink still remain on the
film, the print should be _immersed in water, but only after the benzol
has completely evaporated not only from the film but also from the fibers
of the paper_, and it should then be gently wiped with the finger. Even
if the film still shows a slight tint after this, the working-up may
be begun again successfully, since the traces of the previous inking
disappear under the new application of ink.
This complete removal of the ink with benzol may also be repeatedly
effected. _Beginners can, therefore, use any prepared print several
times for experiments._ But experts should not think of washing an
unsatisfactory print with benzol. Those who possess a transfer machine
can remove the film of ink mechanically in the simplest way by transfer.
_If it is desired to remove the ink from very small portions of the
print_, this is most easily effected by repeated use of _art-gum_, which
should be sharpened to a point. After every application of the art-gum,
a fresh surface of the gum must be used, so that the ink is not again
transferred to the picture. It should be noted, however, that repeated
use of the gum on the same spot may cause blisters.
FAILURES.—To assist the beginner, some possible failures will be here
described.
It may happen that during the inking _the print becomes covered with
fibers and small hairs of the most different shapes_. This phenomenon
may sometimes become so troublesome that a successful print appears
problematical. It is frequently _incorrectly assumed_ that these
impurities are _caused entirely by the brush_. Hairs that have fallen
from the brush are always recognizable as such, for they are straight,
relatively thick, lie entirely on the surface of the film, and can be
easily removed. When there is an excessive appearance of _fibers_, they
are due to the use of an unsuitable cloth for drying. The fibers are of
the most different shapes, from dots to recurved and entangled lines.
From the fact that they always appear most strongly and frequently during
the inking up, it is frequently erroneously assumed that they are caused
by the brush used for the inking, or that dust is deposited from the air;
this is not so. A dirty brush may be to blame; mostly, however, they are
fibers of very different shapes, which are brought on to the damp and
somewhat tacky gelatine film by the pressure of an unsuitable cloth,
which is not free from lint, and they are held fast by the gelatine and
torn from the cloth as this is lifted. At first these thin and almost
transparent fibers are not visible. But they take the ink, and thus it
happens that they seem to appear in ever increasing numbers during the
inking. If _individual_ fibers (which may come from an otherwise suitable
cloth), or brush hairs that have fallen out, have to be removed, this is
readily effected by _art-gum_, worked to a point with the fingers. With
such a point long fibers can be very easily lifted from the film, while
the tiny cloth fibers cling very firmly to the film. A small white spot,
where the gum point has touched, remains, as this removed the ink also
from the gelatine. Such points can be completely closed up by repeatedly
going over them with the brush.
Single hairs or fibers lying on the surface may be allowed to remain,
when they occur in places where for any reason one must not destroy the
ink film; they can be very easily removed from the film with a sharp
instrument in the after treatment of the finished print; usually they
leave scarcely any mark.
If, on the other hand, the fibers have appeared in large numbers, the
print should be immersed in water and one should try to remove them
by gentle friction with the tip of the finger, which is generally
successful, even if the film of ink is also removed at the same time. If,
however, the fibers adhere so firmly that they cannot be removed in this
way, which is particularly likely to happen in the shadows, the whole
coating of ink must be removed in the manner outlined in the previous
section, page 73.
The only safeguard against the appearance of this difficulty is the use
of a material as free from lint as possible for drying the film.
It may happen that _the print takes the first hard ink instantly and
very readily_, but that even with long hopping clearness of the details
is not obtained; the picture indeed shows up well, but remains muddy,
as even the high lights retain the ink and become darker with further
application of the ink. Then, as a rule, the requisite relief has not yet
been attained, and the print must be placed in warmer water. If all the
instructions for the development of the bromide print, the bleaching and
the swelling have been adhered to, and success is still wanting, then the
fault lies in the paper, which was hardened too much in manufacture. The
bromoil process is based on the fact that the shadows are tanned more
than the high lights, and that then the tanned places take up more ink
than the untanned. If the whole film was completely hardened from the
start, there cannot be more tanning added by the bleaching, and the ink
will take everywhere, in the lights and in the shadows.
_If the high lights of the picture completely repel any grade of ink_,
while this adheres thickly in the shadows, then the formation of the
relief has been forced too far.
If the print _takes the ink neither in the high lights nor the shadows_,
there is either a fault in the preliminary preparation, as, for instance,
bleaching in too warm a solution, or one too strongly acidified, or the
print has been acted on too energetically by the ammonia bath. In the
last case the print may be dried and again swollen in water.
_If large or small irregular spots_ which take the ink more strongly
than the surrounding parts, _are formed during the inking_, the reason
is either that the prints have lain one on top of the other in the
preliminary baths, or the film has been prevented from swelling by air
bubbles, or by having risen out of the water. Thus certain places are
less well prepared or are not swollen, and therefore behave as though
they had been more strongly tanned, that is to say, they take even the
first ink strongly and stand out from their surroundings as spots and
streaks. Sometimes such spots are improved by putting more ink on the
print; if they are not of large area and are in the less important parts
of the picture, they may be ignored, as they can be removed from the
finished print without special trouble, as will be explained later. If,
however, the spots have a large area, or occur in an important part of
the picture, for instance, in the eyes of a portrait, it is preferable
to stop further work. As a matter of fact, all such blemishes may be
removed by after treatment of the print, but the trouble entailed by the
correction of large faults is greater than the work of preparing a new
print.
Sometimes darker spots or streaks of irregular outline show themselves
during the work, which from their shape cannot be ascribed either to air
bubbles or to partial sinking of the relief. Then there are probably
irregularities in the gelatine coating, for which the preliminary
treatment of the bromide print is not responsible.
If the print shows a satisfactory relief, but still takes the ink
badly or not at all, the reason is in the incorrect composition of the
bleaching solution, or the _omission of the intermediate drying_ after
bleaching.
Finally it may happen that the image _appears_ almost _as a negative_
during inking-up, since the high lights take the ink quicker than the
shadows. This phenomenon appears when the intermediate drying after
bleaching has been omitted, or if _the work has been begun with too soft
an ink_. In such cases, if too much ink has not been applied, the fault
can be corrected by further working-up with a hard ink. If this is of no
use, all the ink must be removed from the faulty places in the manner
already described.
If during the inking-up _small irregular white spots in groups_ show
themselves and shift their places, then there are drops of water in the
brush or on the print. The print should be dried, the brush also, and the
spots hopped dry and worked over.
_Yellow or brown spots and patches_, which often appear during the work,
increasing in number and continually enlarging, or even penetrating
through the film into the fiber of the paper, are to be ascribed to the
fact that particles of amidol were deposited on the film before the
soaking of the print. When these particles dissolve in water they cause
the trouble just described. If there are merely scattered spots of this
kind which have not penetrated the paper, they may be scraped out of
the finished print and then retouched. The real remedy, however, is in
keeping the amidol carefully closed and as far as possible not in the
same room as the prepared prints.
_Ink streaks_, which a print treated with a soft ink shows when it is
taken out of the warm water, only appear when the print is placed in a
slanting or vertical position; they can be avoided by taking the print
from the water and immediately bringing it into a horizontal position on
the support and rapidly drying, so that the water cannot run off.
The failures caused by the use of the ammonia bath were described on page
46.
ALTERATION OF THE CHARACTER OF THE PICTURE BY THE INKING.—If the inking
is carried out exactly according to the previous instructions, which have
been given chiefly for the benefit of beginners, the result will be a
picture which, as regards gradation, will be like the original bromide
print before it was bleached. The finished bromoil print, produced by
a perfectly even application of ink over the whole picture by means of
successive additions, each thoroughly worked over with the brush, differs
from the original bromide print in coloration, structure, more extended
gradation, and change in the character of its surface. As the worker
is at liberty to stop at any desired stage of the work, he can obtain
from the original bromide print, according to his taste, a delicate
light-toned bromoil or a very rich and highly modulated print, or any
intermediate stage between these two extremes.
Yet these possibilities by themselves alone would not justify the
conversion of the original bromide print into a bromoil. The substitution
of a new photographic positive process for an old one is only justified
if the new process accomplishes something essentially different and above
all something better. But absolutely uniform working over of the bleached
bromide print with greasy inks does not completely fulfil this postulate.
Mere changes of gradation of the whole picture or of its color can
certainly be attained by simpler photographic methods. The extraordinary
advantages of the bromoil process lie in other directions.
_Bromoil printing, for instance, permits us to ink any individual part of
the print more or less, or even not at all, at will_; it is possible to
give enormous brilliance and aerial perspective to the high lights; they
may show when finished every tonal value represented in the negative;
it is also possible to darken them to an extraordinary extent by the
application of more or softer ink. On the other hand, the shadows may
be kept perfectly light by omitting to ink them or by very delicate
treatment, or, by successive applications of the ink, they may be
strengthened to very great intensity and yet retain all their details.
_The worker has wide opportunity for control in the local treatment of
his prints. His dependence on the negative is limited to the drawing,
while in the treatment of the tonal values he is absolute master._ Most
of the other positive processes are dependent on the negative for their
extremes of depth and of delicacy; the bromoil process does not know
this dependence. If it is desired to obtain a delicate picture from any
negative, one uses only a little ink, and hops it off thoroughly; then
there may be obtained from even _the most contrasty negative a delicate
print, but one thoroughly worked out in all its details_. On the other
hand, there is practically no limit to the continued application of ink;
the film is still capable of taking up more ink, long after the limits
of artistic pictorial effect have been passed. The result is that in
the bromoil process _vigor and depth of the shadows can be produced
in any desired intensity_. The most striking advantage of the process
lies, however, in the possibility of changing the tonal values of any
individual portion of the print at will.
If for example, a negative was used in making the original bromide
print which had been taken without any attention to the requirements
for getting correct tones, by suitable treatment in making the bromoil
one can obtain an approximately correct print without special trouble,
since one can, for instance, convert an absolutely clogged-up sky, which
is pure white in the bromide print, to a suitable grey tone by the use
of soft ink, and at the same time lighten foliage which is too dark; a
flat print, wanting in plasticity, may be improved by making objects
in the foreground more vigorous, and accentuating appropriate parts of
the middle distance. It is easily possible to supply the lacking aerial
perspective of certain kinds of prints. In portrait work in the bromoil
process, skilful workmanship renders one absolutely independent of the
nature of the background. A light background can be made dark, a dark
one light. In portraits taken out of doors, the small details of the
background that are out of focus or obtrusive may be omitted, toned
down or completely remodeled. Unpleasing details of the clothing or the
hair can be omitted or so far softened down that they are no longer
disturbing. We are able to accentuate certain parts of the picture to
make them dominant, while other parts of the image may be treated very
sketchily; in short, the possibilities of control which this process
offers are almost inexhaustible.
I will now try to outline the methods of carrying out some of these
modifications, as far as is possible without practical demonstration.
The beginner is first of all recommended to use a proof print from the
negative as a check, so that he may have a clear idea as to what changes
he needs to make, and so that further, in carrying out his ideas, he does
not change neighboring parts of the print which should remain unchanged.
The simplest example of control is the _lightening of the shadows_. This
is done by very careful application of the ink, which is stopped before
the shadow parts become too dark. One should avoid touching such parts
later with the brush, when it is charged with soft ink.
If light portions are to be made darker, the procedure depends upon
the size of the parts involved. Extensive parts of the picture in high
relief, as for instance the sky, should be gone over as evenly as
possible with a suitable soft ink, and with this, simultaneously, by
going lightly over the lighter places and applying it more heavily here
and there, clouds may be put in. The evenness of the inking is of the
greatest importance here, as it cannot later be hopped off very much;
frequently in such cases the ink only lies on the surface, without
adhering firmly; if left untouched, it combines intimately with the
surface when the print is dry, but is easily removed by hopping. It is
possible to change the outlines of neighboring parts of the image; if too
dark edges are formed, they can be easily softened by after treatment of
the finished print. In some cases it may be necessary to add considerable
quantities of varnish or linseed oil to dilute the ink. The darkening of
too light places may be also effected by dabbing ink with the brush on
the finished dried print, which the print then naturally takes all over.
_If tiny light patches are to be made darker_, the point of the large
brush, or if necessary of a very small brush should be used, avoiding
any disturbance of surrounding parts, as far as possible. Such changes
are difficult only when the bright spots that are to be worked out are
in immediate contact with very dark parts. The process is much simpler
when parts of the print of medium tones, which are surrounded by lighter
parts, are to be darkened. If, for instance, the eyes of a portrait are
to be darkened, ink should be applied to the whole of the eye with a
small brush, and then hopped off. A tree trunk, which must be brought
out in relief, should be covered throughout its whole length with soft
ink, and the ink should then be worked over, by hopping it from the
lighter toward the darker parts. In practice, the bringing together of
neighboring tones, which differ considerably in value, can be easily
effected by _hopping off the ink from the darker parts_ with a brush
that has not been freshly charged with ink, _and depositing it on the
lighter parts_. The lightening of too dark places can also be attained by
going over them with a perfectly clean brush that has not been dipped in
the ink. Isolated high lights can be accentuated by touching them with
a pointed water-color brush, dipped in water; then the film swells and
repels the ink. _Stained high lights or too dark middle tones_ may be
lightened by wetting a brush of proper size by means of a wet cloth and
then lightly hopping with this the places which are to be corrected. The
brush picks up the color, but must be immediately cleaned by rubbing it
on a clean portion of the palette, after which it may be again wet and
used again. Clouds can be worked into dark parts of the sky in this way.
THE STRUCTURE OF THE INK.—Independently of the surface of the paper on
which the work is done, _the structure of the coating of ink can be
influenced by the nature of the brush work_. If a brush well charged with
ink has its full surface placed firmly on the gelatine film and then
slowly lifted up, an impression of the surface of the brush remains; the
individual hairs or groups of hairs of the brush have each deposited a
part of the ink that they had taken up, and a very coarse-grained spot
of ink is produced. If we now hop, that is, dab with quick light blows
of the brush, the ink begins to be distributed, since it is taken away
from the lighter parts and taken up by the shadows. The drawing of the
picture _thus appears under the brush, at first with a very coarse grain
and without many details_. The longer one hops and thus distributes
the ink, the finer becomes the grain, and it especially becomes much
finer on the addition of softer ink. _The bromoil printer hence has it
completely within his power to limit the division of the ink to any
desired coarseness of grain_, assuming, of course, that he has suited
the consistency of the ink to the degree of relief, and is therefore
able to completely finish the print with the original ink without
adding any softer. Prints may thus be prepared, which because of their
coarse structure, resemble certain graphic methods. But, when this is
intended, the application of the ink must be carried on as evenly as
possible from the beginning, so that it needs very little hopping off,
for any considerable amount of hopping unavoidably produces a finer
grain. Even if the use of softer inks is necessary, a coarse structure
can be obtained by suitable brush work. _The longer, however, the ink is
distributed by hopping, the finer becomes the structure of the ink film_
and the smoother the surface.
_The most perfect smoothness is also attainable_, if it is desired for
any reason. For this a not too volatile solvent should be used, such as
heavy benzol. The method of using this is as follows: when the print has
been fully inked and is complete, though still somewhat coarse-grained,
a cloth should be wet with the benzol, and the brush lightly pressed
thereon and then passed quickly over the desired parts of the picture. At
first a smeared spot is formed on the surface of the print; by continued
gentle hopping the spot is gradually worked out, and by continued working
we get a fineness of detail, equal to that of printing-out paper. It is
true that even the highest lights acquire a delicate film of ink, so
that a print treated in this way is somewhat low in key. If the hopping
with the brush charged with benzol is not continued until the finest
possible grain is attained, a misty effect may be produced, with some
suppression of the finest details; a method which is frequently useful in
the production of landscapes.
By suitable ink and brush technique the effect of any other known
photographic printing process may be attained in bromoil printing, from
the rich-in-detail gloss of collodio-chloride paper to the characteristic
effects of gum-bichromate. Yet the far-reaching possibilities which
bromoil places at our command really only begin where most of the other
processes end.
DIFFERENT METHODS OF WORKING.—In the following pages some of the
different methods of technique, which the bromoil process permits, will
be briefly sketched. Obviously, however, the description of these methods
cannot be made complete without practical demonstration. Nor can all
conceivable methods of working be mentioned, as individual treatment of
the process can be varied in many ways.
We will first describe the method of working which is most suitable _for
the beginner_, because it offers tolerable certainty to those who have
not yet mastered the process.
The beginner, in order to obtain good results, must start with a bromide
print as clean and well-modeled as possible, and its high lights should
not be fogged in the least. He should place the print, bleached and
prepared exactly according to the methods detailed in this book, in water
at about 18° C. (65° F.), leave it there for a few minutes, dry its
surface, and begin the application of the ink with the stiffer ink, which
should be thinly applied and then worked over until the hopping brings
out no further detail. If the drawing of the image does not quickly
appear upon hopping the print, and the result is only a detailless patch
of ink, the original temperature of the soaking bath must be increased.
Then the print should be again immersed in the water, left for two
minutes, and again dried. The work of hopping is now continued with the
same brush with which the print was originally treated, _and without its
having been again put into the ink_. As a rule the mere placing of the
print in water again will have increased the contrasts, and new details
will have appeared, which can be considerably accentuated by now going
over with the brush. Only when the print has been again worked over,
should fresh ink be carefully applied with the brush; this should then
be distributed by hopping, and the print again soaked in water. The
procedure thus outlined: application of the ink, hopping, soaking, going
over it with the empty brush, fresh ink application, hopping, soaking,
and so on, is continued as long as the print gains in strength and depth,
without becoming dull or muddy. If, however, this point is reached, the
inked print should be immersed in water at a rather higher temperature
and left in it for some minutes. The print is then further treated with
the brush, without fresh inking, and will soon become much clearer in
the high lights. If the clearing thus obtained is not sufficient, the
temperature of the water bath should be increased by a few degrees, but
not more than 5° C. (9° F.) at a time. As the high lights become clearer
it may happen that the stiff ink will no longer be taken up. Then it is
necessary to soften it a little. This method of working will guarantee to
the beginner the attainment of good results with tolerable certainty.
HARD INK TECHNIQUE (_Coarse-grain Prints_).—If it is desired to prepare a
bromoil print of _rough surface and coarser character_, the worker must
be able to finish the print exclusively with a relatively hard ink. For
this it is necessary to determine by trial the temperature of the water
bath at which the film of the print acquires a relief which is absolutely
suitable for the stiff ink. When this degree of relief has been found,
the print should be inked up strongly but evenly from the very start, so
that one is not compelled to go over individual places several times with
the brush. Thus the coarse structure of the ink is obtained. The use of
hog’s bristle brushes is also efficacious in coarse-grained work.
SOFT INK TECHNIQUE.—This method of working is used on the one hand for
the preparation of low-toned misty effects, on the other hand to obtain
fully and richly modeled prints. In the first case the bromide print
should be correctly exposed, but not completely developed; while in
the second case it should be thoroughly developed. The print is then,
according to the choice of the operator, either brought at once to a
fairly high relief, or only gradually raised to the same relief during
the application of the ink. Then, in the course of inking, a point is
soon reached at which the stiffer ink is repelled by the high lights
and perhaps also by the lighter half-tones, and during the hopping is
again taken up by the brush. Then the ink should be carefully softened
with linseed oil or varnish, and the whole print gone over with the
softer ink. Prints which are executed in the soft ink technique are
characterized by a specially fine velvety surface after defatting.
SKETCH TECHNIQUE.—If one proposes to completely work up certain parts
of a print and leave the rest treated in a sketchy manner, and possibly
to omit some parts altogether, one should begin by working up the part
which should stand out. Thus, in a portrait, the head should be first
worked up; then proceed systematically, with the ink remaining in the
brush, to sketch in the clothing and the background, and perhaps leave
unimportant parts of the print completely untouched. To facilitate the
work, disturbing details or a too prominent background may be removed
or reduced on the bromide print, before bleaching, with dilute Farmer’s
reducer. If, when the work is finished, the parts that have not been
inked are visible through their relief and glossiness, these traces of
the uninked picture completely disappear in drying, if the original
bromide print was not developed too vigorously. If one contemplates
producing a vignette, it is absolutely unnecessary to obtain this by the
use of masks or vignetters when making the bromide print. The effects
which result from the suitable treatment of the bromoil print are far
more free and beautiful.
If certain parts of the picture are to be accentuated and all the rest is
to be rendered visible, even if only sketchily, one may also work in the
reverse way. The whole picture should be given a thin coating of ink, as
even as possible, which should be hopped only just enough to barely bring
out the drawing. Then work out those parts, to which attention is to be
directed, keeping as closely as possible to the outlines. When these, the
most important parts of the print, are finished, it is frequently seen
that the rest of the picture is too delicate. This should then be gone
over again with the ink as at first, without completely working it up,
until the correct tonal value is attained. Then the necessary harmony is
obtained by going over the outlines with the brush.
LARGE HEADS.—The far-reaching possibilities of the bromoil process offer
special advantages for the free modification of tones in portraits. It
is advisable to take the portraits with a neutral or dark background.
The only exception is when a head is to be done in red chalk, when a
white background is preferable. Starting from such a negative in bromoil
printing the background may be kept, according to choice, either light or
very dark, or be shaded. One precaution should, however, be observed in
every case; before starting on the head itself, the background should be
worked in lightly from the margins toward the head, so that no dark line
may be formed when working on the outlines of the portrait. If this shows
during the work, it must be worked down to harmony with the background at
once before it gets too dark. One can, therefore, from a given negative,
produce at will either a fully worked-up head against a dark ground,
or a light, sketchy image on the light background of the paper, or any
intermediate stage.
If, as previously suggested, parts of the picture are to be treated
sketchily, while others are to be fully worked up, the parts which should
appear sketchy are allowed to remain coarse-grained, while the structure
gradually becomes finer in passing into the worked-up portions. No
portion, however, should be made perfectly structureless. Bromoil prints
thus worked up are much more artistic than those pictures which are known
by the name of photo-sketches. The latter usually show a head, printed
with all the gradation and fullness of detail given by printing-out
paper. The tone becomes gradually lighter toward the edges, where we
find some strong lines, imitating the character of a line drawing, all
surrounded by a perfectly white background. To the trained eye the
technique of such photo-sketches is abominable, for the contrast between
the inimitable detail of the head and the perfectly blank background is
so great that it cannot be bridged over by the effort to imitate the
manner of an etching. On the other hand, such problems can be solved in
an artistic way with our process, for the head may always be produced
in a rather coarse grain, so that it dovetails harmoniously into the
sketchily treated surroundings.
OIL-PAINTING STYLE.—If it is desired to prepare portraits which resemble
reproductions of oil paintings, one should proceed as follows: the head
should be first inked in considerably deeper than it should appear in the
final print; then, if the head is on a light background, it will appear
vigorous, even if not much ink is used. If, however, the background
is dark and heavy, the inked-up head will appear considerably lighter
because of the contrast. For this style of work it is best to select a
warm dark brown ink. When the head is finished, some very soft ink of
the same shade should be placed very thickly in the corners and margins
of the picture, and this should be worked from all sides towards the
head, which naturally must not be touched with the soft ink. Finally the
blending of the head with the background should be very carefully done.
In the lower part of the portrait the clothing should blend into the
background in a similar manner; only one must take care in making the
negative that no light pieces of drapery or accessories are used, because
they cannot be easily completely covered. Any lighter accents, which may
be desired in the background, should be made by removing the ink with
a clean brush. One may thus make the head stand out in a dark oval, or
attain similar painting effects. Prints prepared in this way ought not to
be defatted, as they then lose their similarity to oil paintings. They
must be left to dry for several days, in a place free from dust, until
the thickly-applied ink has hardened.
NIGHT PICTURES.—Twilight and night effects can be easily obtained from
ordinary negatives by carefully swelling the bleached print so that the
differences of relief existent in the print are only slightly brought
out. Then the capacity of the lights and shadows for taking the ink is
not so very different, and the gradation is shorter. A second possibility
of obtaining the same effect is offered by using mainly soft ink, which,
as is well known, adheres to a certain extent even in the high lights of
the print; only the soft ink must be applied very carefully and thinly in
the shadows, so that these do not become choked up with ink.
In this way one may make night pictures from daylight exposures,
accurately corresponding in tone values to night exposures. Previous
practice has been to use either underexposed negatives or overexposed
prints for such effects; in both cases the night effects were gloomy,
but false in tone values, and usually without details in the shadows. In
bromoil printing the gradation can be shortened as described, without
loss of drawing, and one can simulate perfectly the short scale and
mysterious gloom of night. If the too dense sky of the negative cannot
be sufficiently darkened by the use of soft ink, its inking should be
postponed till the print is dry.
PRINTS WITH WHITE MARGINS.—If it is desired to obtain bromoil prints
with _margins of the natural paper_, the negative should be masked with
clean-cut black safe-edges of lantern slide binding strips, or one may
use a mask, and print or enlarge on a sheet of bromide paper large enough
to leave unexposed margins of the desired width. In making enlargements
the mask, cut out of rather thin card, should be pinned on the enlarging
screen over the sheet of bromide paper. After bleaching such a print the
tanned image will appear slightly depressed within a strongly swollen,
white frame of less tanned gelatine. The inking is done without any
attention being paid to this unprinted edge. In consequence of its strong
relief this gelatine does not take any ink from the brush, or, at most, a
mere trace. When the print is finished, the ink is easily wiped from the
white margins by means of a damp cloth, which removes this ink with the
greatest ease. The finished and dried print is enhanced in effect if a
plate mark is impressed in this wide white margin.
THE SWELLED-GRAIN IMAGE.—Coarse-grain printing in bromoil has previously
depended on a very carefully determined relation between the degree
of relief of the film and the consistency of the ink, which had to be
so chosen that the ink was not very easily taken up by the film. If
inking was then skilfully done, the structure of the face of the brush
was visible to a certain extent all over the print and gave the effect
of a more or less coarse and irregular-grained image. It was obviously
necessary for the success of a print of this type that no portion of
the image should be gone over several times with the brush, for, if
this was done, the structure was obliterated and the spot in question
became smooth. Since, also, the requirement that the degree of relief
must be rather high for the chosen consistency of the ink could never
be fulfilled by the shadows, since these always take the color easily,
we often obtained an undesired smoothness of effect in the shadows. For
this reason typical coarse-grain prints could not always be produced with
certainty.
I therefore endeavored to improve the technique of bromoil in this
respect and to work out a grain method which could be depended upon with
certainty in every case. The basic thought was that _the fundamental
basis for making a coarse grain print should be a part of the film
itself_, and I endeavored to prepare the latter so that a grain structure
could be produced which should equally underlie all parts of the image.
Such a grain structure can theoretically be obtained in the following
way: if we allow a properly prepared uninked bromoil print, which has
been brought to the proper degree of relief, to dry off a little and
then spray it by means of an atomizer with extremely fine liquid drops,
the film will again swell up under every drop, but only under these;
and when we ink up, we obtain a definite grain effect which, however,
only persists if the inking is completed before the sprayed-on water
grain again dries out. Such a relief grain is not permanent, because the
subsequently swollen portions of the film cannot retain the difference
in swelling. This process, therefore, has only experimental interest and
practically can be used but rarely.
To make the swelled grain useful, the secondarily swollen points of the
film must permanently retain the difference in swelling which has been
imparted to them.
To attain this end, I start from the fact that portions of the gelatine
which are treated with alkaline solution will swell much more in a bath
of warm water than spots which have not been thus handled. If, therefore,
the desired grain can be applied to the film by means of an alkaline
solution, all the elements of the grain will swell up more strongly in
the water bath than their surroundings, and will therefore protrude
above the rest of the film and thus attain and retain a better degree of
swelling than the latent tanned image.
The next step was obviously a practical treatment of the film by spraying
it as evenly as possible with extremely fine drops of an alkaline
solution. It soon appeared that the greatest attention must be paid
to the type of apparatus with which the spraying was to be done. Any
atomizer whose spray combines fine and coarse drops is useless. Any
atomizer which is worked by blowing with the mouth or by intermittent
blasts of a pump is unsuitable, for at the instant when the stream
of air is interrupted, a certain quantity of liquid remains in the
mouthpiece and is thrown out by the next blast of air in the form of
coarse drops. Therefore, only continuously functioning atomizers can be
used, preferably those types which are actuated by double rubber bellows.
Only with such atomizers is it possible to count with a fair degree
of certainty on the production of a system of uniformly fine drops.
Ammonia, which has previously been generally used in bromoil printing as
a swelling agent, cannot be used to produce such a grain, because the
ammonia gas volatilizes in great part in its passage through the air. A
five per cent solution of potassium carbonate has been found to be most
satisfactory.
The next question is at what stage of the process the swelled grain
should be produced. Making it on the dry print is not permissible,
because the droplets are taken up too greedily by the dry film and
diffuse quickly and irregularly. The safest method of working is to place
the bleached and dried print in cold water until it becomes limp, then
blot it off until quite dry on the surface, and then treat it.
The practical method of producing the swelled grain is as follows: the
print, which has been swelled in cold water and thoroughly dried off, is
placed on a horizontal support and the atomizer set in action; as soon as
it works with complete uniformity, it is passed back and forth across the
print as evenly as possible under continuous observation, until the whole
print is uniformly covered with a layer of extremely fine drops. The most
important precaution is the continuous observation of the print while the
spraying is being done, and this is best done by having the light fall on
the print at as small an angle as possible. The practical way to do this
is as follows: the print is laid on a table near the window. The operator
sits in front of the window and gets both his eye and the atomizer very
slightly above and in front of the print. Under these conditions there is
a reflection of light in every single drop, which makes the observation
of the distribution of the drops very easy. At the instant when the whole
film seems to be uniformly covered with dew, the atomizer is quickly
turned away from the print.
It is necessary to be thoroughly familiar with the action of the atomizer
which is being used; with most atomizers the finest drops, on account of
their lightness, fall downwards not very far from the mouthpiece, while
others project their finest drops to a greater distance. The sprayed
print, which naturally cannot be touched on the film side, must be left
undisturbed for a certain period, which must be determined by experiment,
for it depends, among other things, on the temperature of the room and
the peculiarities of the paper which is used. An approximate idea may
be had by considering these points: the longer the potassium carbonate
solution lies on the print, the more the finest drops evaporate, while
somewhat larger drops continue their action, so that the grain becomes
coarser through longer action. A coarse grain can also be obtained by
the use of coarse drops. If the drops are allowed to dry completely, the
diffusion produced during this longer time results in an extra swelling
of the whole film, without any grain effect.
After a sufficient time has elapsed, the potassium carbonate solution
is removed from the film by rinsing or blotting off, and the print
is swollen to the necessary degree. It is obvious that much lower
temperatures must be used for this than if the print had not been treated
with the graining solution, for the drops of the potassium carbonate
solution cover a considerable fraction of the surface of the print.
The fact that the greater portion of the surface of the print has been
affected by the spray makes it apparent that the alkaline solution
cannot be replaced by a tanning solution, for the greater portion of the
film would become less capable of swelling if such a solution were used,
and therefore the latent tanned image would be destroyed. When the print
is blotted off after swelling, it should show a scarcely visible relief
when looked at by light falling from the side. The actual effect of the
grain cannot be perceived until after the inking has been done.
The prints obtained in this way have, if the treatment has been
successful, a very beautiful grained structure which extends over the
lights and shadows quite evenly. It is possible to work on such a print
quite normally without having to harmonize the degree of relief and the
consistency of the ink with great accuracy. Especially is it possible to
work up any given part of the print as long as desired with the brush
without endangering the structure; on the contrary, it is improved by
this treatment. For bromoil transfer, there are the following special
advantages: every new transfer has exactly the same coarseness of grain,
if this is imparted to the film once for all. In combination transfer,
the grain persists in spite of the fact that several impressions are made
on the same paper, because the swelled-grain elements are re-impressed in
the same spots, if the registration is accurate.
Finally, it might be well to mention a few causes of failure which
frequently occur in the first experiments. If the print appears to be
covered with many small white spots at a certain distance apart but not
in contact, the grain is too heavy and therefore does not take up enough
ink. In this case, after rinsing, the print may be sprayed once more,
carefully and not too heavily.
Larger white spots on the print show that when the grain was made large
drops were produced by the atomizer. If such drops are noticed while
spraying, the print should be immediately placed in water, dried off and
sprayed again. If the print shows spots of rather large area which do
not take ink and only show irregular ink spots here and there, it has
been sprayed too long, that is, too much potash solution was applied, and
the print is then useless as it cannot be corrected. In addition, such a
print may be easily recognized after swelling, for a coarse grain pattern
will be clearly visible on the film.
This swelled-grain process permits of very beautiful and characteristic
results, yet, like all variations, it assumes a solid knowledge of the
bromoil process, and must be practically used over and over again before
it can be applied with certainty.
MIXING THE INKS.—As has already been mentioned, we have at our command
for bromoil not only black and brown, but any other color of ink in
various shades.
As a rule, however, colored inks are somewhat too bright to be used pure;
moreover, as a rule they can only be had commercially in a fairly soft
consistency. This is actually no disadvantage, as one is often forced
by the consistency of the ink to do what is counselled by good taste,
that is to tone down the colored ink with hard black ink. It is not
practicable to make a mixture of hard black ink with the colored with the
knife on the palette, because it is difficult to hit the exact shade with
certainty in this way. It is better when using green, blue or any other
colored ink _to mix the inks with the brush on the bromoil print itself_.
First one should go over the whole print very delicately with hard black
ink and almost complete the drawing by hopping. Then the work should be
continued as would be done if we were mixing hard and soft ink, merely
replacing the soft black ink by the colored one. Then the work should be
continued with the mixed ink; if the exact shade has not been hit, more
or less of one or the other color is taken up by the brush until the
desired color effect is obtained.
It is immaterial that those parts of the print on which one has tested
the mixture show a little too bright or too dark a tone. By going over
these again with the final correct color these places, though perhaps
only after resoaking, will reach the proper tone, as the ink in the brush
and that already on the print quickly mix to a uniform value.
If, in the course of the work, it appears that the mixture of this and
the colored ink, the color tone adhere properly, it is not advisable
to attempt further softening by the addition of soft black ink. By the
mixture of this and the colored ink, the color tone already decided on
will be altered. In such a case varnish or linseed oil must be used to
soften the mixed ink.
POLYCHROME BROMOILS.—Prints of two or more colors have previously been
made, aside from the three-color process printed from three-color
separation negatives, chiefly by the gum-bichromate process, by coating
the print successively in different colors. After each coating the
negative was printed, usually with masks, and the unnecessary parts of
each colored coating were washed away during development. The preparation
of a polychrome gum print is extremely tedious and uncertain. Not the
least of the difficulties is the fact that in consequence of the
addition of the chromate the color effect cannot be determined with
accuracy until the print is finished and the chromium salts are removed.
Moreover, as a rule the color layers are perfectly distinct and the color
mixtures formed by their juxtaposition must be accepted as they happen to
come. A correction of the colors during the work is not easily effected.
_The bromoil process, on the other hand, is in its very essence
preëminently suitable for work in several colors, and offers all the
possibilities which have previously been lacking. Without any special
preliminary preparation the worker can apply any number of different
colors to one and the same print at one sitting; he can harmonize them to
each other during the progress of the work, combine neighboring colors by
working them into each other on the print and easily correct any error
that may occur._
It is true that the execution of a bromoil print in polychrome requires
complete mastery of the process; an indispensable condition is a perfect
command of the handling of brush and ink. Therefore, experiments in
polychrome bromoil printing can only be recommended to those who have the
monochrome process absolutely at their fingers’ tips.
If a negative is to be printed in several colors, the worker must first
be absolutely clear as to his artistic scheme and know exactly in what
color each individual part of the print must be executed; he must further
be sure that the chosen colors harmonize with each other. He will not
always be satisfied with the colors to be found in commerce, but must
prepare the necessary inks for himself.
At first pictures should be chosen which contain large areas of uniform
coloration, and as few colors as possible should be used. If you are not
perfectly familiar with the print, it is necessary to have a proof as a
guide, so as not to overstep the outlines of the different parts of the
image which are to be individually colored.
The best way of setting to work is as follows: first select the color
necessary for one or more of the larger areas of the picture, for
instance green for the foliage, and work up these areas completely,
until they have acquired the requisite vigor and detail. Such parts of
the outlines as are adjacent to lighter, and hence more strongly swollen
parts of the print, need be given no special attention, for color that
does not belong on them may easily be removed again with the damp cloth,
as previously mentioned. On the other hand it is well to work carefully
with every outline which lies next to a darker part of the picture which
is finally to be of another color. Here it is best not to apply the
ink right up to the boundary, but to complete the inking with a small
brush only after the adjacent parts are coated with their own color. If,
however, such outlines are overstepped and the adjacent parts are colored
with an ink that should not be applied to them, this should be removed
with a very wet cloth, twisted to a fine point, by gentle rubbing.
During this the print should remain on the pad. If the incorrectly inked
portions are small in area the ink may be removed with art-gum.
When the first large areas are finished, the print should be again
soaked in water, as it will probably have dried somewhat, then dried
off, and another part of the picture dealt with, with a fresh color.
If the adjacent colors are properly chosen, the result, with objects
which have no sharp outlines but merge into one another, will be that
the adjacent parts will spontaneously blend into a harmonious transition
of color. Parts of the picture which have the same basic color must not
be done throughout in one and the same shade; thus large stretches of
vegetation, which extend into the distance, should be executed in front
in a yellowish green, and should be shaded back into a bluish green and
insensibly into blue in the distance; such transitions can be effected
without difficulty. If in the shadows there are small parts which require
another color, they should be inked with a very bright color, which is
then reduced by going over the whole surface at one time.
If it is found that a mistake has been made in any color, that part of
the print may be cleared of ink as described on page 72, and the work
repeated. If it should finally appear that individual colors are too
glaring or that the whole color scheme is too harsh, it is possible to
go over individual parts or the whole print with some suitable color, so
that the colors already applied are improved by a slight admixture of
this covering color.
Such a procedure shows most emphatically what advantages there are in the
possibility of mixing and toning down the colors on the print itself. As
a rule, to tone down too bright colors, these portions or even the whole
print are gone over with black ink, but if necessary other colors may be
used for the same purpose.
Thus, for instance, a picture in which there are brown roofs,
yellowish-green foliage, a sky of a pronounced blue shade and water of
another blue, can be made harmonious by going over the whole print very
lightly with the blue of the sky. Thus the vegetation will lose some
of its yellowish tone, and all other colors, without losing their own
characteristics, will acquire a certain unity. If the sky parts of a
picture are swollen too much, their uniform inking is not easy. Then it
is advisable to ink up the sky only on the dry print, as is suggested on
page 112.
Because the tonality of any color, which has already been applied, can
be altered with the brush, polychrome bromoil printing affords very
great possibilities. Obviously good taste and a sound color sense are
indispensable requisites, for without them there is danger of producing
the undesirable effects characteristic of certain colored postcards. It
may also be remarked that the colors, after defatting, have a somewhat
less pronounced brilliancy, as they lose their gloss.
In polychrome bromoil printing, the choice of too small sizes is not to
be recommended. The larger the picture is, the larger also are the areas
which may be uniformly treated and, therefore, the easier it is to keep
within the outlines.
Within the limits of this chapter, it is not possible to teach polychrome
bromoil printing, only to outline its fundamentals. The unlimited freedom
which it offers will certainly in the course of time produce many
excesses in color. For this, however, we should condemn, not the process
itself, but those who have abused it. In general it will be as well not
to approach too closely the actual colors of the objects represented,
but to work for the attainment of artistic effects. We must, however, in
any case avoid even the most remote imitation of the painter; we cannot
arrive at the solution of the problem of natural colors on paper by the
polychrome bromoil process.
CHAPTER IV
AFTER-TREATMENT OF THE FINISHED PRINT
The film of ink on the dried bromoil print after the completion of the
brush work is as a rule not very tender, except where much soft ink lies
on the surface. It is not advisable, however, to put the print under
pressure, as for instance in a printing frame, for under strong pressure
the ink may still partially offset on the adjacent paper, so that the
image is damaged. No pressure should be applied until after the removal
of the fatty medium, which is described later.
When the brush work is completed, the whole surface of the bromoil print
shows a slight gloss, caused by the fatty medium of the ink. The shadows
show a stronger sheen, especially in those places where there is more
soft ink, for soft inks contain more medium. The surface of the print,
so far as the gloss is concerned, is like that of a finished gum print.
But with the latter the gloss cannot be removed; when it is desired to
get rid of the unpleasant property of gum prints, that the shadows are
more glossy than the rest of the print, it is necessary to make the whole
print glossy by painting it with a solution of gum. This is also the case
with the carbon process.
_With the bromoil process, on the other hand, it is easily possible to
remove the gloss entirely._ The shininess of a finished bromoil print
is especially unpleasant when seen sideways, but, in certain cases,
it imparts depth to the picture and may be made fairly inoffensive
by glazing the print. Prints which are to keep their gloss must be
exposed to the air for some days, protected from dust, until the ink has
completely hardened. Until this has happened, the surface of the picture,
especially where the ink is soft, is sensitive and ought not to be
touched.
DEFATTING THE INK FILM.—Before removal of the fatty medium from the ink,
_the print must be absolutely dried out_. It must be so dry that it rings
sharply when the finger is snapped against it. Also, the dish in which
the defatting is to be carried out must not contain the slightest trace
of moisture, otherwise trouble will be caused.
An easily volatile solvent of the fat, such as benzol, trichlorethylene,
carbon tetrachloride, etc., should be poured into the dish, and the
print immersed in the liquid and allowed to remain for some minutes
with constant rocking. On account of the danger of fire from the
vapors of benzol, no naked flame should be allowed in the room. Carbon
tetrachloride (carbona), on the other hand, is non-inflammable; its
solvent action, and that of the trichlorethylene, on fats, is much more
rapid than that of benzol.
The film of ink is, as a rule, not damaged by the solvent, though
care should be taken with prints which have been executed wholly or
mostly in soft ink. With such prints it may happen that the ink is
entirely dissolved in parts, or that irregular sharp lines and streaks
are suddenly formed. Soft ink prints should, therefore, be allowed
to dry for several days before they are defatted. By the use of very
energetic solvents, such, for instance, as trichlorethylene and carbon
tetrachloride, soft ink prints, as a rule, are completely dissolved.
_Benzol is, therefore, to be preferred in all cases._
The print should be removed from the liquid without touching the ink
film, softened by the solvent. This evaporates fairly quickly, and _now
the bromoil print has an absolutely matt surface of great beauty_. It is
here naturally assumed that the fatty medium of the ink is soluble in
benzol, which is usually the case.
_The solution of the medium from the fatty ink, besides the removal of
the gloss, has also the effect of fixing the surface of the picture and
making it more resistant._ While the film of ink before the defatting is
fairly tender, it afterwards has a stability at least equal to that of a
pencil drawing. The surface of the finished bromoil print is generally at
least as little liable to damage as the film of prints prepared by other
photographic methods. It seems as if the very minute grains of pigment
contained in the fatty ink are made firmly adherent by the drying of the
somewhat tacky gelatine film and therefore remain fixed even after the
removal of the fatty medium. It is only from places in which a specially
thick layer of soft ink was deposited, that a trifle of pigment dust can
sometimes be removed by light friction.
_The defatting is therefore a procedure which is advisable in most cases
and only after this is the bromoil print actually complete._ After it has
been carried out, the image consists of pure mineral pigment adhering
firmly to the gelatine. It is self-evident that a print treated in such a
way is absolutely permanent, provided that the inks used are non-fading,
which is almost always the case. One can also subsequently moisten or
soak the print without any danger if, for example, it is to be mounted on
cardboard.
RETOUCHING THE PRINT.—The defatted bromoil print is susceptible to the
most far-reaching mechanical modification. The picture now consists,
as already mentioned, entirely of extremely fine particles of pigment
adhering to the film about as strongly as the lines of a pencil drawing.
_This pigment can also now be treated with rubber exactly like a pencil
drawing. The ink, as far as it was put on by degrees, can also be removed
by degrees from any desired place by proper measures._
In the finished bromoil print the deepest shadows are formed by a
comparatively thick layer of pigment, while the lights have only a
very delicate coating of ink. We are consequently able to diminish the
thickness of the film by proper treatment, removing it layer by layer,
so that the shadows become more transparent, or the film of ink may be
entirely removed, so that the gelatine base is laid bare.
The best tool for this is a piece of a hard rubber eraser sharpened to a
fine point with sandpaper or a file. It is also advisable to use a very
soft sharpened eraser for treating very light places.
Every part of the print which is to be lightened should now be gone over
with the point of the rubber in fine lines very close together. The ink
powder, which is taken up by the rubber, must be removed from time to
time by rubbing the rubber on the sandpaper, or it will be left on the
print again in the form of dark lines. If gentle rubbing with the eraser
does not have the desired effect, it should be used more energetically.
Sometimes the ink adheres so firmly that the rubber must be used quite
vigorously in order to remove it. On the other hand, where soft ink has
been applied, one must work very lightly, or more ink may be removed than
is desired.
_Important details of the picture may be completely taken out with the
rubber_ without getting down to the paper, if the work is done carefully.
Thus, for instance, unsharp figures in the foreground of a street scene,
disturbing details in the background of a portrait, undesirable details
of a landscape, such as telegraph wires, ugly poles, trees, etc., may be
removed almost without leaving a trace behind. If this treatment does
leave visible marks, they can be easily made to disappear with brush and
ink.
For removing or lightening tiny spots or lines, or for removing brush
hairs and similar imperfections left during the inking, one may use a
sharp _lancet or penknife_, or a steel needle set in a handle. Yet in the
use of these sharp instruments one must be careful to scrape the surface
very gently and carefully, or the gelatine film may be cut, which leaves
noticeable marks.
The possibility of removing the ink from the finished print in layers
by the use of an eraser, without leaving any trace, gives the bromoil
printer another means for modifying the tone values of the print at will.
If preconceived ideas were not fully carried out in the application
of the ink, because tiny places could not be properly worked out with
the brush, or because they were overlooked, the desired change of tone
values can now be effected; with the aid of the rubber, also, _especially
effective lights_ may be added to the picture.
_If, in the application of the ink, large areas were not quite uniformly
treated, they can be corrected now without trouble. Dark spots of ink can
be easily removed with the rubber, and it is often easier to even out a
rather broken surface with the eraser than with the oil-printing brush._
Bare spots, white points, and other defects of the image, or places
from which too much ink has been removed with the eraser or penknife,
are best spotted with _water-color_ of proper shade, or in the case of
brownish-black prints, even with charcoal. The defatted film takes the
water-color easily and places treated with it remain perfectly matt; on
the other hand, _retouching with lead pencil should be avoided whenever
possible_, as this always produces a certain shininess, which is rendered
particularly prominent by the dull surface of the rest of the print. A
bromoil print which has not been defatted may also be retouched in the
same way, but the parts worked up with the rubber are then noticeable.
Filling up spots on such prints is best effected with oil-printing ink,
applied with a water-color brush dipped in heavy benzol so as to dilute
it.
It is thus possible in the bromoil process to produce very comprehensive
changes with rubber, needle and ink, without destroying the character
of the picture. With some experience this work is done so quickly and
easily that it is not necessary to retouch the negative at all, even
with portraits. The removal of imperfections in the complexion or the
softening of too sharp features can be effected much more quickly and
with more certainty as to the effect on the finished bromoil print than
on the negative, especially as retouching on the negative shows up
unpleasantly in enlarging.
The possibilities of after-treatment of a bromoil print are manifold.
Thus, for instance, by means of the eraser very natural appearing clouds
can be rubbed into the cloudless sky of a landscape not taken with
an orthochromatic plate, if in inking the sky is properly darkened.
In the background and subordinate planes of a portrait, a certain
draughtsmanlike character can be attained by suitable delicate strokes
with the rubber. Ugly lines of the hair or clothing which could not be
suitably dealt with in the inking-up, can now be altered with a little
skill. A dull landscape may be made more lively by picking out a few
lights.
Finally, it may be mentioned that it is also possible _to change the
color of the paper base of the print_, though this is best done before
the application of the ink. Commercial bromide papers as a rule are only
obtainable in white or yellowish tints. Another tone may be imparted
to the paper, for instance reddish or bluish for certain effects; this
is effected by swelling the bleached and fixed bromoil print in a dye
solution which has been found suitable by preliminary trial with white
paper. The paper fibers and the gelatine assume the desired color and the
print after soaking is removed and worked up as usual; this staining may
also be done with finished prints.
REFATTING OF THE PRINT.—As already mentioned, the finished bromoil print
shows on its surface places with different degrees of gloss, since the
parts of the picture which took a good deal of ink, as for instance the
shadows, are more shiny than the rest. In order to remove these sometimes
unpleasant effects; the finished bromoil print can be immersed in a fat
solvent, which completely removes the glossy medium from the ink film.
After the evaporation of the solvent the bromoil print has a perfectly
matt surface.
Frequently, however, this complete dullness of the surface does not
please the worker, because, especially with soft ink prints, it causes
a marked _loss of brilliancy_. It is thus necessary to choose between
a brilliant surface with unequally glossy places, or a uniform matt
surface. I have undertaken experiments to place in the hands of the
bromoil printer a means of imparting to his prints any desired degree
of gloss, after removal of the unpleasant uneven shininess. Attempts
to obtain brilliancy by the use of ordinary varnishes failed. Whether
the varnish was sprayed on or the print was immersed, there was always
a certain damage to the surface, since the ink film, which lies rather
loosely in the form of powder on the defatted soft ink prints, combined
irregularly with the varnish and caused some trouble. I was finally
successful with the following plan, which is a logical consequence of the
nature of the bromoil print and the varnish inks used in making it.
Dissolve from 5 to 10 ccm of linseed oil varnish in 500 ccm of benzol
(77 to 154 minims to 16 oz.). Then the defatted and perfectly flat print
is completely immersed in this solution for one minute and hung up to
dry. Perfect flatness of the print is necessary, otherwise troublesome
markings are formed in drying, which, however, may be removed without
difficulty by repeating the process. Irregularities may also be caused by
supporting the print by the fingers on the back before hanging it up; the
warmth of the fingers evaporates the solvent more quickly, so that spots
are caused. The print should only be handled by the edges until it is dry.
After the evaporation of the solvent, the linseed oil varnish dissolved
therein is very evenly distributed throughout the whole film of ink;
this restores to the ink a part of its varnish which was removed in
the defatting, but more evenly distributed, so that now the whole
print shows a gloss, which is hardly noticeable, but which considerably
increases the brilliancy. If this gloss is not sufficient, more varnish
should be added to the bath; if it is too strong, more of the solvent is
added. In this way any degree of gloss desired can be obtained. If it is
too strong, it can be removed again with benzol. When the bromoil print
is to be retouched it should be defatted before retouching and afterward
treated as just described, so that the varnish bath may also act on the
retouched places.
If no retouching is required, then the defatting can be effected in
the varnish bath, which then effects a kind of equalization, since the
shadows rich in varnish give up the medium, while the other parts of the
picture take it up.
By the use of weak varnish baths for after treatment of defatted bromoil
prints, surfaces of velvety appearance may be obtained.
APPLICATION OF INK TO DRY PRINTS.—When the gelatine film has been swollen
to the highest possible relief even the very soft inks take only with
difficulty and in consequence frequently irregularly. Sometimes the
formation of such places is unavoidable, especially when prints with
very great contrasts have to be used. We are then forced to choose a
relief which permits the inking of the darkest parts of the print.
The warm water, or ammonia, bath requisite for this acts so strongly
on the slightly tanned or untanned parts, that an excessive relief is
obtained, and then the ink takes with difficulty or not at all. This most
frequently happens with skies which are very dense in the negative.
Such parts of the print, resistant while it is wet, can, however, be
inked up without difficulty after the print has been allowed to dry.
Then they are inked up with a brush, using an ink of the same tint and
consistency as was used in making the bromoil print itself. The dry
gelatine takes the ink quite evenly, and in this way any desired tone
from the most delicate to the darkest may be obtained. By omitting to ink
in suitable places, clouds may be imitated, and if necessary these may be
worked up by retouching.
With polychrome bromoils, when the skies are too swollen, one should
carefully remove all areas of ink which project from the landscape into
the sky, and this is also advisable in monochrome work. The best thing
to use for this, especially with complicated outlines, is a water-color
brush dipped in two per cent solution of ammonia, which easily removes
the obtrusive ink from the gelatine. Larger areas should be carefully
rubbed with a point of wet linen or with the finger tip wrapped in a
wet cloth. In this way the highly swollen parts of the gelatine are
completely freed from ink; then the print should be dried and the sky
inked up as desired in the manner described above.
The method of applying the ink to the dry film is valuable for obtaining
other effects, as is more fully described in the next chapter, on bromoil
transfer.
In bromoil, photographic printing has been enriched by a process that
can fulfil every wish of the photographer who is striving for artistic
results. It combines in itself all the advantages of previously known
processes, but surpasses them all in the possibility of general and local
control, and especially in the fact that control can be effected at will
at any desired step of the process from the beginning to the end, that it
need not extend over the whole print but may be limited to particular
parts, and that the results of the control are visible immediately,
during the work. Not the least important, however, is the fact that the
flexibility of the process enables one to immediately repair any error
without impairment of the print. When it is further considered that the
bromoil process is independent of the size of the negative, that it
permits the operator to use any support, any structure, any grain and any
color, we should be warranted in saying that the bromoil process is the
process of the future for amateurs striving for artistic results.
CHAPTER V
TRANSFER METHODS
SIMPLE TRANSFER.—Bromoil prints, which have been inked up but not
defatted, can be effectively used as print-plates, from which pulls
on any desired plain paper can be taken. The process of making such
transfers is simple and certain and opens a whole series of new
possibilities to the amateur. Briefly the method is as follows:
The greasy ink on a finished bromoil print lies on a gelatine film. If
the inked print is brought into contact with any uncoated paper and
passed between two rolls under pressure, the ink transfers from the
bromoil print to the paper. Obviously the picture thus produced is
laterally reversed, which must be kept in view in preparing bromoil
prints for transfer. Bromide enlargements to be used for transfer should,
therefore, be made reversed.
The bromoil print can again be inked up after this process and again used
for transfer; with bromide papers with resistant gelatine films this
process may be repeated many times.
The advantages which bromoil transfer offers are as follows: in the
first place we attain the end so often sought of being able to use any
suitable paper for making photographic prints, which opens a new field
for artistic endeavor. Obviously, also, any desirable oil-printing ink
can be used, so that the whole gamut of colors is at the command of the
operator.
The personal control of the tone values of the print, which attains its
maximum development in bromoil printing, is equally possible in bromoil
transfer.
The picture is obtained on an uncoated paper and, therefore, the prints
are of a character which hitherto could scarcely be obtained.
The finished prints, if the paper is properly chosen, can be retouched as
much as desired.
From a single bromoil print a whole series of impressions can be
obtained, which may either be all alike or quite different. They can
be made heavy or light, in one or more colors, or even in polychrome,
according to how the re-inking is done.
The transfer process is also very cheap, as the papers used are naturally
much cheaper than photographic printing papers. Moreover, one can make
the pulls from small bromoil prints on larger sheets, so that the picture
may be suitably surrounded with white margins.
The following details should be observed in the preparation of bromoil
transfers:
The bromoil print designed to be used as a print-plate can be made on
papers of the characters described in Chapter I, page 13. The bromide
paper need not necessarily be free from structure, for with the pressure
to which the sheet is subjected in the transfer, the effect of the
structure is lost. The structure of the bromide paper may also be reduced
by passing the bleached print through the rollers of the transfer machine
under heavy pressure before inking. _The bromide print or enlargement
must be kept very clean and free from fog_, since the cleanness of the
high lights plays a very important part in the transfer. The inking is
done in the usual way; only one should use all possible means to obtain
the greatest possible cleanness of the high lights, and good modulation.
After inking-up, any brush hairs and especially any little particles of
ink that are not broken up must be removed, as the latter are especially
troublesome in the transfer.
The process succeeds best when the bromoil print has as high a relief
as possible. Such a relief facilitates and requires the use of inks of
soft consistency; soft inks adhere to the gelatine film far less firmly
than harder ones and, therefore, transfer very much more easily to the
transfer paper. A simple experiment makes this fact very clear: if the
tip of the finger is placed on a part of the bromoil print worked-up with
hard ink, some of the ink sticks to the finger, but at the most there
is formed on the print an impression of the tip of the finger, as the
place touched still retains the greater part of its ink. If, however,
the tip of the finger is placed on a part of the print worked up with
soft ink, the latter will be almost entirely removed. This may serve to
show why bromoil prints which have been entirely or chiefly worked up
with hard ink cannot be entirely transferred to the transfer paper. The
shadows especially, when covered with hard ink, are likely to appear much
reticulated in consequence of the imperfect transfer of the ink.
_To obtain with certainty a faultless bromoil transfer, soft ink should
therefore be used_; the softening of the ink must naturally not exceed a
certain limit, because otherwise the high lights will take the ink and
a clean pull cannot be obtained. In order to be able to use a soft ink
successfully, the relief of the bromoil print must as a rule be kept
rather high; hence usually water baths of suitably high temperature
should be used. It may, however, happen, especially with contrasty
prints, that the gelatine in the high lights becomes too soft, and if it
is not already damaged when taken from the warm water, it pulls off in
inking-up or in the transfer. In order to avoid this, it is best to use
the ammonia bath described on page 45.
Bromoil prints which are to be used for transfer must, as already
mentioned, always be kept very clean. This is necessary for the following
reasons. In the transfer the ink on the high lights transfers completely
in every case to the transfer paper, for the high lights are in the
highest relief, and the ink adheres to them very lightly. On the other
hand the ink is generally not completely removed from the shadows, as
they have the lowest relief and, in consequence of their tanning, the
ink adheres to them more tenaciously. Thus it happens that the transfer
is usually somewhat shorter in gradation than the original bromoil.
Allowance must be made for this, and the bromoil print should be made
considerably more brilliant than the transfer ought to be, unless
low-toned transfers are intentionally sought.
In order to obtain clean, sharp edges the bromide print when dry should
be cut to the desired size and a small tab of paper left at one corner,
which is useful for hanging it up in the further processes, whereby any
damage to the film of the picture itself is avoided. This little tab
should be cut off just before inking. If a plate mark is desired, the
print should be made with a suitable narrow white margin.
The finished bromoil print can be immediately used for the transfer. If
it is not used at once, it remains fit for transfer until the ink begins
to harden.
Any desired kind of paper may theoretically be used for the transfer;
but obviously, the success of the transfer greatly depends on the choice
of the paper. The finest effects are obtained on matt and absorbent,
but strong and well-made papers, the very best being papers intended
for copper-plate printing. As the ink penetrates into the fiber of
such papers to a certain extent, they give beautiful transfers with
an absolutely matt surface. Absorbent papers also make it possible to
transfer almost all of the ink from the bromoil. It is different with
sized or highly calendered papers. With these, the ink only penetrates
a very little way because of the film of size. The ink, therefore, lies
chiefly on the surface of the transfer and appears glossy in the shadows;
also, as it is not sufficiently absorbed by the transfer paper, the
transfer of the ink from the bromoil to the paper is usually not complete.
It is advisable, when using calendered paper, to remove the gloss by
preliminary dipping in water. Other kinds of paper also frequently give
better transfers, if they are first moistened; this is most easily done
by dipping them in water and then drying them between two blotters.
Papers which are inclined to blister because of short fibers easily split
in transfer, as parts of the surface of the paper adhere to the high
lights of the print and tear away.
Such papers may be made available for transfer, if they are coated
with two per cent wheat starch paste and allowed to dry (Process of E.
Guttmann). This is prepared by stirring up 2 g (60 gr.) of wheat starch
in a little cold water, and adding to the mixture 100 ccm (3½ oz.) of
actually boiling water, stirring well and allowing to cool.
The blistering of weak papers must be differentiated from the sticking to
the transfer paper of parts which are too much swollen; in this case the
surface of the paper remains undamaged, but the gelatine film of the high
lights is torn off and adheres to the transfer paper. As a rule, this
only occurs with those parts that are swollen too much, when too great
pressure is used in the transfer. The preliminary sizing of the transfer
paper with wheat starch prevents this also. Parts of the gelatine film
which have high relief may also be protected from sticking to the
transfer paper by a slight coat of varnish.
The best machine to use is that described by E. Guttmann on page 153. It
has proved satisfactory in every way, especially as it permits accurate
and easy regulation of the pressure of the rolls. If such a press is not
available, an ordinary burnisher can be used. The simultaneous movement
of the rolls in burnishers is produced as a rule by two gear wheels.
The inaccurate fitting of the gear teeth, however, causes periodic
irregularities in the pressure, which cause trouble in the transfer. In
order to prevent this one of the gear wheels should be removed, so that
the simultaneous movement of the rolls is produced by the pressure alone.
A burnisher is useful for the preparation of transfers only if it is
possible to obtain sufficient pressure on the rolls. On the other hand
it is difficult to obtain with this machine the necessary regulation of
the pressure during the transfer, which is described in the following
paragraph.
The following is the procedure in transferring. A blanket must first
be interposed between the rolls of the press. The best thing to use
for this is two or four thin smooth cards, which may be covered at
top and underneath with two sheets of thin linoleum. The latter are
not absolutely necessary. The print may now be introduced into the
machine either by entirely removing the blankets, or by rolling them
out far enough so that the middle sheets can be easily bent away from
one another. The position of the transfer on the transfer paper should
be marked with a pencil, and, if a plate mark is desired, a piece of
cardboard cut to the proper size should be properly placed on the
transfer paper, and the whole passed through the machine. The transfer
paper, thus prepared, should be laid on a perfectly flat white blotter,
and the bromoil print, which should be held very carefully by the extreme
edges, should be lowered to the position on the transfer paper previously
marked with the pencil. Any small ink marks thus caused can be easily
worked out later. The back of the print should be dried with a white
blotter and then a second sheet of the same size as the bottom one placed
on it. The transfer paper with the print lying on it is thus placed
between the two sheets of blotting paper, so that the water pressed out
in the transfer may be readily absorbed.
If attention is not paid to this precaution, it may easily happen that
the transfer paper, as a result of partial moistening by means of water
pressed out of the bromoil, may become wrinkled or distorted. Then the
two blotters, with the transfer and the print between them, are placed
between the two middle cards and the transfer begun. The principle of
gradually increasing the pressure in this, which was introduced by E.
Guttmann, has proved satisfactory in practice. One begins first with
a light pressure, so that the transfer passes through the rolls with
scarcely noticeable resistance. Then the pressure should be increased
a little by tightening the upper wheel of the machine, and the work
continued in this way until a certain, not very high pressure of the
rolls is obtained, which one soon learns to estimate with a little
experience. One can now, or at any later stage, take the transfer paper
with the adhering print out of the press and, holding one part of the
print firmly down on the transfer paper, with the hand or a straight
edge, lift the free end carefully, in order to ascertain whether any and
how much of the ink has been transferred from the print to the transfer
paper.
According to the result of this observation, the print is either entirely
lifted off or the transfer continued with increasing pressure. In this
way, with careful management of the work, one is absolutely certain of
obtaining the best possible results in transferring. Still, my opinion
differs from that of the inventor as to the reason for the satisfactory
action of the gradual increase of the pressure. What happens is that in
the initial passage under low pressure the print is immediately firmly
attached to the transfer paper, so that its shifting on the transfer
paper, which previously very frequently occurred, is avoided. When this
adherence is once attained, we can proceed at once to that pressure of
the rolls which is the most favorable for the transfer of the ink, if
we are sure of it. This frequently happens when one has already made
transfers from a print. With still unknown conditions, naturally the
gradual increase of pressure is advisable.
The print, removed after the completion of the transfer, can be again
inked up immediately or later, and again transferred. Naturally it must
first be immersed in water, so that it can again take up that which it
has lost in the transfer. In the new inking-up one can use as desired
the same ink or another color, and also alter the print as seems best. If
the bromoil print, which has been once used for transfer, is to be again
used for the same purpose, it is well to completely remove any adherent
traces of ink by going over it with a swab of cotton soaked in a solvent.
It may then be dried and can be used again at any desired time.
When transfers have been repeatedly made from a bromoil print, it may
happen that the film blisters. This phenomenon is usually only noticeable
when the print is again immersed in water after the transfer; as long
as the blisters are not too numerous, they do not cause much trouble
in the transfer. The answer to the question as to how often a bromoil
print can be transferred depends on the resistance of the gelatine film.
In practice it has been observed that the number of possible transfers
varies between five and twenty-five.
The transfer process can also be used in bromoil printing as a method to
free a print that has been too heavily inked from the excess of ink; such
a print is passed through the machine together with any completely smooth
paper which is free from folds, until it has given up its excess of ink
to the paper, and it can then be soaked and inked up anew.
The process of application of ink to the dry print, outlined in Chapter
IV, can also be used to advantage in the transfer process. Any bare
spots on the finished transfer can be inked up at will, by dabbing on
ink of any tone value with the oil-printing brush; thus the sky, which
may not be satisfactory, may before transfer be wiped quite clean on
the print, the outlines of the landscape cleared up with a brush dipped
in ammonia water if necessary, and the values of the sky put in on the
finished transfer. This procedure is particularly advisable in polychrome
transfers, with which a blue sky flecked with clouds can be easily
obtained in this way.
The subsequent application of ink to the finished transfer finally offers
the possibility, by tinting the whole transfer with a very delicate
coating of a suitably chosen ink, of imparting a different mood to the
picture. Thus, for instance, one may give a transfer made on white paper
a faint yellowish tint; it may be effective to surround the picture with
a border of this tint, using a suitable mask to obtain sharp outlines;
this yellowish tint is only visible in the high lights, as it does not
show in the deep shadows. In similar fashion a darker tint surrounding
the print may be put on with ink and brush.
It is obvious that the transfer, especially when fresh from the press,
can be easily and thoroughly retouched with rubber, water-color or
charcoal; first of all those places should be treated from which the ink
has been removed in consequence of the unavoidable touching of the print
with the fingers, or to which the ink has not transferred for any reason.
With transfers fresh from the press, any places that are too dark can be
easily lightened with the rubber.
The transfer very soon dries. Obviously it does not require defatting.
The inks act better on the absorbent transfer paper than on the bromoil
print itself, as they sink into the paper instead of remaining on the
surface of a gelatine film. The final result no longer resembles a
bromoil print, but has its own individual character and is a product
which it is difficult to compare with the bromoil print as regards
esthetic effect. The bromoil print has a certain charm which is lacking
in the transfer and vice versa. In any case the transfer process is worth
attention, since on the one hand it can be of practical value because of
the possibility of the duplication of bromoil prints, and on the other
hand it enables one to use varieties of paper which were not hitherto
available to the amateur.
COMBINATION TRANSFER.—In order to render possible the reproduction
of every possible tonal value of the negative, I have worked out the
_combination transfer process_ outlined in the following paragraphs. The
essence of this process lies in the fact that two or more transfers can
be made on one transfer sheet, which differ so much in their quality that
_each of them reproduces a different series of tone values_, which then
supplement one another on the transfer.
This is attained either by executing the two superposable transfers
with _inks of different consistency_, or by _the use of two prints of
different gradation_ to make one transfer.
COMBINATION TRANSFER WITH ONE PRINT-PLATE.—The bromoil print used as the
print-plate must be made on a sheet of bromide paper, which reproduces
the tone values of the negative as closely as possible, without showing
any hardness. The lights must be clean and all the half-tones present;
it is, however, neither necessary nor desirable that the shadows should
be too dense. In making the bromide print from a moderately difficult
negative one should use the process, outlined on page 23, or developing
slightly and then completing the development in a dish of water. Bromide
prints of this kind are necessary because they satisfy the most rigorous
requirements in the high lights and half-tones, while the depth lacking
in the shadows is produced by the repeated transfer.
On the print thus prepared two bromoil prints, differing entirely from
each other in character, are made, one of which we will call the _shadow
print_ (Kraftdruck) and the other the _high light print_ (Lasurdruck).
This phraseology does not coincide, however, with the similarly named
terms which are familiar in gum printing; the middle-tone print usual in
gum-printing is wanting here and is also unnecessary, since each of the
two partial prints contains a part of the middle tones, and, therefore,
when added together, they give a picture perfectly correct in tone.
The _shadow print_ is executed by inking up with a stiff ink, so adjusted
to the relief that only the deep shadows and a part of the half-tones
take the ink, while the delicate half-tones are lost and the highest
lights remain absolutely uninked. Having suitably adjusted the ink to
the relief, one should also use the corresponding brush technique, which
was described as hard ink technique on page 87. The use of a hog’s hair
brush is advisable. Perfect cleanness of the high lights, which is very
important, should be assured by the use of art gum. The shadows must show
the full drawing, but ought not to be overinked. This shadow print should
now be transferred to the transfer paper; when it leaves the press, the
_registration marks_ must be immediately applied, so that the subsequent
transfer may come exactly in the same place. It may be remarked, that
the matching of the print to the transfer does not offer the slightest
difficulty in practice, and that the registration marks can often be
omitted entirely, especially with prints which are inked right up to
their edges, because bromoils, in making which rather thick paper is
used, leave a fairly strong impression on the transfer paper, into which
one can fit the print in the subsequent transfer.
At the same time it is safe to use the following simple registration
arrangement in every case.
When the transfer is taken from the press, draw, by means of a rule, two
parallel lines perpendicular to the side edges of the print, running over
onto the transfer paper about one centimeter or one-half an inch apart.
Also draw with the rule a line perpendicular to the upper surface of the
print, also running over onto the transfer paper. In preparing for the
next partial print, the side lines are first to be brought into exact
coincidence and then the upper line. This insures exact coincidence for
the subsequent prints.
After transfer of the shadow print, the bromoil is again immersed in
water, in which it must remain for some time, so that it again becomes
saturated with water. Only then does it regain the same size as it had
at first, for the expansion caused by the absorption of water is quite
considerable. If the bromoil is not left long enough in the water before
the second printing, it will be slightly smaller than in the first
transfer and the combination print will not be sharp.
HIGH LIGHT PRINT.—The inking up of the high light print is effected with
soft ink, so as to produce a very thin and smooth film of ink; yet here
too the high lights must be kept as clean as possible. Then this high
light print is transferred by means of the above described registration
arrangement, when as a rule the combination transfer is finished.
It may happen that one has inked up one or other of the prints too
lightly. In this case either the shadow or the high light print may be
repeated, but the amount of ink applied for this supplementary impression
must be very carefully judged, in order to avoid an overinking of the
combination transfer. By the manner of inking the constituent prints
and judgment in the quantity of ink applied, the final result may be
controlled through a wide range at will; one can, for instance, by
emphasizing the shadow print rather than the high light print, get more
contrasty effects, or, by emphasizing the high light print, end with very
soft effects.
The order in which the two prints are transferred is immaterial. In any
case, however, care must be taken that the transfer paper is well dried
out after making the first transfer; for it always takes up some moisture
in the press and then appears slightly wrinkled and distorted. If the
second transfer is made on such a damp transfer paper, the result will
obviously be complete or partial want of sharpness in the combination
transfer. After the first transfer, therefore, the transfer paper should
be hung up to dry spontaneously, not by heat, as otherwise it may alter
in size.
The process just outlined for combination transfer from a single print
will in most cases perfectly reproduce the tone values of an ordinary
negative. If negatives with a very long gradation have to be dealt with,
then the following process may be used.
COMBINATION TRANSFER FROM TWO PRINTS.—The underlying idea in using two
prints is to overcome the impossibility of completely reproducing an
extended scale of tones on bromide paper, by the use of two prints, which
are so made that they divide the scale of tones in such a way that one
end of the scale is represented by one print and the other end by the
other.
Therefore we make from the negative one hard print with well modulated
shadows and only the darker half-tones. This is obtained by short
exposure and suitable development. The high lights should show no deposit
of silver. When master of the process, it is possible to include more or
less of the middle half-tones in this partial print which is intended for
the shadow print, according to the final result desired, and this can be
readily regulated by the length of the exposure. The fewer middle tones
the shadow print contains, the more contrasty will be the combination
transfer.
The second partial print is the high light print, and must, therefore,
be kept as delicate and soft as possible, and include all the delicate
middle tones up to the highest lights. The latter may even be very
slightly veiled, yet only so far that after swelling absolutely pure
whites can be obtained. No further demonstration is needed to prove that
a combination of these two partial prints can include the whole scale
of tone values of the longest-scaled negative; for the partial print
destined for the high light print-plate gives every possible half-tone,
while the other, intended for the shadow print, imparts full depth to the
shadows without burying the details, and strengthens the half-tones, but
does not affect the clearness of the high lights.
The combination transfer is now prepared from these two prints, which
are transferred in succession to the transfer paper, the order being
immaterial. For this an accurate superposition of the two partial prints
is absolutely essential. This must be accomplished by making the two
prints of exactly the same size, with the images in exactly the same
position on the paper. This may be done by masking the negative with
black lantern-slide strips gummed on the film for contact prints and on
the glass for enlargements. The strips must be absolutely straight and
the slightest curvature avoided in sticking them down. Two prints or
enlargements, prepared from such a negative, can easily be registered.
The desired end may also be obtained by printing or enlarging the two
bromide prints under the same straight-edged mask. Care must be taken
here that the image occupies exactly the same place in the mask for both
prints. This is easily accomplished with various commercial printing
machines. In enlarging, a mask made of stiff card can be hinged to the
easel. The prints or enlargements thus made should be very carefully
trimmed along the white margins and the difference in size ought not to
exceed one-tenth of a millimeter (one two-hundred-fiftieth of an inch).
Further, as different papers have different degrees of expansion, it is
necessary to use the same kind of paper for the two partial prints, and
it is best to take it from the same packet. It is also necessary to make
both prints in the same direction of the paper fibers, for the expansion
is different with and across the run of the paper.
One of the partial prints is transferred just as in the previous method.
The registration marks are also made as was previously described, only
the pencil marks must be placed exactly at the same points on the two
partial prints, which can be done by exact measurement. With this
process, also, the registration is not difficult in practice and the
careful worker will find that the impression in the transfer paper caused
by the first partial print, supplemented by the two lines on the edges,
is sufficient.
The inking up of the two partial prints is effected in the same way as
was outlined for the process with one print-plate.
Both variants of combination transfer offer operators with a little
dexterity a wide range of possibilities. By suitable treatment of the
partial prints the tone gradations can be controlled at will. The
resultant transfer will be softer or harder, as the shadow or the high
light print predominates; it is possible to omit certain portions in
either of the prints or subsequently print in more deeply any parts
which need special strengthening; the two prints may also be executed
in different shades of ink, with suitable discretion, and double tones
thus obtained. It is also possible to print in clouds from a separate
negative. Combination transfer is also well suited for polychrome
transfers, since it renders possible the overlaying of a delicate black
impression with different color tones. Again, since all the possibilities
of control offered by the bromoil process are available, an almost
unlimited new field of activity is given by combination transfer.
Finally, there is still another field in which the combination transfer
allows remarkable effects. If one has a negative with excessive
contrasts, as for instance, a dark arch with a vista of a sunny
landscape, a satisfactory print can be made without difficulty by means
of combination transfer. One partial print should be so made that it
reproduces as correctly as possible the details of the dark part of
the negative, in this case the arch, irrespective of the fact that the
sunny landscape will be partly underexposed. Another partial print is
then exposed for the sunny landscape, when naturally the details of the
arch are completely lost. One may even go further still, since the two
partial prints may be prepared from two negatives taken from the same
standpoint, the one being exposed for the high lights and the other for
the shadows. A combination transfer, correctly executed from two such
partial prints, gives a result in which both the darker and the lighter
parts of the negative are reproduced in suitable tone values. It may also
be mentioned that multiple transfer renders it possible to apply plenty
of ink to calendered and, therefore, non-absorbent papers, and thus
permits of the attainment of deep shadows, full of detail, on such papers.
In the various kinds of multiple transfer here outlined principles have
been introduced into the transfer process which have been used in the
gum-bichromate process and many graphic reproduction processes, in order
to produce wide ranges of tone values by several printings on one print.
Yet the means of attaining this end are novel, namely, either different
consistency of inks with one print-plate, or the use of two different
print-plates for one transfer.
In my first publications on such combination transfer processes, I
mentioned still a third possibility of obtaining the desired end, namely
the preparation of two partial transfers from one print by using two
different degrees of relief. The process first outlined, using different
consistencies of ink with one print, is, however, to be preferred to
the process in which two reliefs are used, wherefore the latter was not
further proceeded with.
The value of the transfer process has been so increased by the methods
just outlined that it is capable of solving the most difficult
photographic problem, and by its aid even negatives can be printed, which
cannot be satisfactorily rendered even in bromoil. While hitherto the
transfer process was only an offshoot of the bromoil process it is, since
the introduction of combination transfer, at least as valuable and in
many cases even surpasses it.
CHAPTER VI
OIL _vs._ BROMOIL
OIL PRINTING AND BROMOIL PRINTING.—Oil printing and bromoil printing
are frequently considered as two different photographic processes. From
this premise different conclusions have been drawn, thus for instance,
that oil printing is more suitable for certain subjects and that bromoil
printing is to be preferred for other purposes. There has also been
discussion as to which of the two processes deserves the preference,
which produces the finer artistic effects, and so on.
All these discussions are, however, superfluous, for the assumptions on
which they are based are erroneous. Oil printing and bromoil printing are
actually not two essentially different techniques. In both cases there
is one and the same process; _oil and bromoil printing are basically
identical_. This can be proved both theoretically and practically.
_The theoretical considerations_ are as follows: in most photographic
processes the chemical property of certain substances of being changed
by action of light is used for the production of the final image.
Such photochemical processes only play a preparatory rôle in oil and
bromoil printing. The production of the final image is here based on
a physical property of the gelatine, namely on its innate possibility
of being tanned or hardened. In oil and bromoil printing an image is
first formed in the gelatine photochemically. This image is, however,
not the final one; it is merely a means to an end. Its actual
purpose is the attainment of a suitable tanning of the gelatine. The
photochemically produced image is therefore removed, but in such a way
that simultaneously with the elimination of the image, the gelatine
which carried it is proportionately tanned in the lights and shadows of
the picture. Only by this tanning is the gelatine made ready for the
production of the final picture. The purpose of these preliminary steps
is the production of the tanned image in the gelatine, which by itself
is invisible or scarcely visible. After carrying out the preliminary
processes the result is a pure gelatine film, which shows places of
greater and lesser tanning corresponding to the photochemical image which
has disappeared and which, therefore, has greater or lesser capacity for
swelling in these places. If at this stage there are still chemicals in
the film they are of no value for the further processes.
If a gelatine film thus prepared is swollen in water, the untanned places
suck up water, while the tanned parts do not take it up. Fatty inks,
applied with suitable brushes, are then repelled by those parts of the
gelatine which hold the water, while the tanned parts of the film freely
take the greasy ink. The final image, therefore, is not formed until the
inking-up of the film with greasy inks.
_This technique may, therefore, be most suitably characterized by
the name “inking-up process.” The usual names oil print and bromoil
print merely designate, although in terms which are terminologically
unsatisfactory, two methods of preparing the base for the inking-up
process._
Oil and bromoil printing are, therefore, nothing more than the two
methods which have hitherto been at our disposal for the production of a
tanned image in gelatine.
Both methods lead to the same result; only the bromoil method is by far
the more complete technically, as is shown in the following discussion.
In oil printing, printing is effected direct on a bichromated gelatine
film. The chromate image is only faintly visible and is not easy to
judge. From its nature it has a very short scale of tones and, therefore,
only gives satisfactory prints from soft harmonious negatives, while
with more contrasty negatives it must inevitably fail; if with such
negatives the high lights are correctly printed, the shadows have long
lost all details; if the shadows are correctly exposed, the high lights
are wanting in detail. Control of the chromate image is only possible
to a very moderate extent. This chromate image is washed out and leaves
behind as a result the tanned image in the gelatine, in which all the
disadvantages of the short scale of tones are inherent, and which besides
this can be far less easily inked-up than a tanned image prepared by the
bromoil method.
The process of bromoil printing has been fully explained in this book;
a direct comparison of the two processes will be made very briefly. A
correct print is prepared on a suitable bromide paper, either by contact
or enlargement. Through the possibility of using direct enlargement, the
enlarged negative, necessary in oil printing, is done away with. The
bromoil image, in contradistinction to the chromate image is visible, and
can be controlled in the most varied ways to attain the desired artistic
effect. It has a much greater scale of tones than the chromate image; and
this can in addition be increased in the subsequent processes far beyond
the possible gradation of the bromide print. The resulting bromide image
is then removed by a bleaching solution containing bichromate, and in
this way the tanned image is formed in the gelatine.
_Oil printing and bromoil printing, therefore, lead to the same
result; but the tanned image, obtained by way of the bromoil print, is
qualitatively of much greater value, for it has a much better gradation._
The opinion is frequently expressed that it is a specific property of the
oil print to give pictures of a peculiarly artistic character.
It is, however, absolutely erroneous to assume that the same effect
cannot be obtained in a bromoil print. As already mentioned, the tanned
images produced in the two methods are alike, but the bromoil print may
have a far longer scale of tones.
The rich gradation of the bromoil print is however not present from the
beginning, but is only produced by allowing it to swell in water of
suitable temperature. The warmer the water used, the longer is the scale
of tones, naturally within definite limits.
_In bromoil printing it is therefore entirely at the choice of the
operator whether he will or will not make use of the long scale of tones
which the process can give._
If cold water is used for the soaking, the gradation of the tanned image
is much less than that of the oil print or the bromide image. _By the
choice of a suitable temperature of the water, the short gradation of
the oil print with all its peculiarities can be exactly obtained._ With
higher temperatures the gradation may be finally increased far beyond
that of the original bromide image.
If one knows and has mastered the properties of the tanned image produced
by the bromoil print, one may easily obtain the same effects as with oil
printing; one can, on the other hand, obtain incomparably more than with
the latter. No limitation is imposed on artistic aims by the imperfection
of the tanned image.
The following shows the _practical comparison_ of the two methods:
if we have before us prints with gelatine films which contain tanned
images, of which one has been produced by the oil process, the other by
bromoil, they behave absolutely alike in the inking-up, for the bromoil
print receives, by soaking in cold water, a gradation which is just as
short as that of the oil print. _The two prints absolutely cannot be
differentiated in practice_, and are indistinguishable, if the paper, on
which the gelatine film is supported, or the structure of the gelatine,
does not give one a hint.
_In such cases it is impossible to determine from the finished print
whether the picture was made by oil or bromoil printing._ The portfolios
of some of my friends furnish striking proof of this; the authors
themselves can no longer recall by which of the two processes some of
their earlier pictures were made.
Nevertheless the opinion is often held that one can obtain pictures
of much finer artistic quality by means of oil printing, because the
prints thus made have a characteristic tonality and better treatment of
masses. This opinion may be explained by the fact that oil printing has
been used longer and is better known than bromoil, and that first class
bromoil prints have not often been exhibited in public until recently.
Especially, it has not been widely known how manifold are the effects
that can be produced by the different methods of working described in
this book.
There is also another explanation. Whoever has completely mastered any
process and has kept in view a definite artistic purpose, will as a
rule find that the process will give him the results which he desires.
It is now an indisputable fact that even such an imperfect process as
oil printing has many times, because of this very imperfection, led to
results which have been proclaimed as artistic. If for instance, an oil
print is made from a contrasty negative, the process cannot correctly
reproduce the tone values of the negative. The short gradation sets a
limit to the inking-up, before the tone values of the negative are fully
developed. The result is then certain to be a gloomy print with heavy
masses. Technically, however, this means nothing more than that the
high lights are not clean and the shadows lack detail. This does not
imply that the resultant picture may not have an artistic effect. _The
question is only whether this effect was actually tried for_ or whether
necessity was not made a virtue and the imperfections of the process
called an advantage. _Without question, the worker who intentionally
strives for a given artistic effect can attain this easily and certainly
by means of bromoil._ If, however, he has no definite aim, but allows
himself to be blindly driven on, as it were, by the idiosyncrasies of
the process, it may happen that he will obtain quite another result.
The greater gradation of the bromide print may induce him to keep on
working on the picture until he finally obtains a print, which exactly
corresponds in tone values with the gradation of his contrasty negative,
which could not happen with the oil print. In such cases one often hears
the opinion expressed that the special quality of the oil print cannot
be attained in bromoil, and that a similar result could be obtained by
any process, even printing-out paper. But the fault does not lie in
the bromoil process, but in the fact that the worker has not mastered
it, and has been carried beyond his aim by its greater possibilities.
_Oil printing is satisfactory when one desires a shorter gradation than
is present in the negative; beyond this, however, it fails. Bromoil
printing, on the contrary, permits on the one hand the shortening of the
tone gradations of the negative to any desired extent, on the other hand,
however, the extension of the gradation beyond that of the negative._ It
offers, therefore, to the artistic aspirant a far greater liberty and in
every respect a technically more perfect and therefore more effective
instrument. By bromoil printing, therefore, one can prepare at will from
a given negative, either a low-toned picture without detail, or one
richly modeled and full of detail and vigor. _Oil printing does not offer
this alternative._
If, in spite of all this, erroneous ideas as to assumed fundamental
differences between oil and bromoil printing, and particularly as the
special suitability of oil printing for certain effects are still
disseminated, the reason usually lies in the fact that many who have
previously worked in oil have drawn erroneous general conclusions from
their first and naturally imperfect results in bromoil printing. They
overlook the fact that even the worker experienced in oil printing must
first learn bromoil printing and then practice it thoroughly in order
to master it. The oil printer does not bring to it anything beyond
a brush technique, which is not sufficient for every bromoil print.
Everything else must be newly acquired; especially an actual mastery
of the technique of bromide printing, which many lack, though they
believe they possess it. Conservative thought easily overvalues its
own possessions and is likely to show itself somewhat antagonistic to
new accomplishments which cost new efforts. The worker who spares no
trouble to make himself a thorough master of bromoil printing will be in
possession of a technique which renders feasible, by its extraordinary
many-sidedness and capacity of expression, the solution of the most
difficult problems of artistic photography.
CHAPTER VII
BROMOIL TRANSFER
BY EUGEN GUTTMANN
The idea of transferring a bromoil print to an ordinary, uncoated paper
was first introduced by the English and later further worked out by
the French. The Germans turned to this new process comparatively late,
but obtained fine results. Yet the practice of this beautiful form of
artistic photography was limited to a small circle of adherents, and
even to-day, when bromoil printing, thanks to the instruction of some
excellent textbooks, has become known to almost all artistic workers, one
cannot state that it enjoys wide popularity. This may well come from the
fact that not everyone has the absolutely necessary printing machine, and
that the substitutes for this machine, such as burnishers and washing
mangles, cannot bring out all that lies in the process. In addition, when
the process was first introduced, the transfers were never strong enough,
and were mostly muddy and flat. This happened because, in the first years
of the process, strong and vigorous shadows were not produced on the
paper. The English and French improved this by pigmenting the shadows of
the bromoil print much more strongly than was needed for this process.
They stated that the chromated film took the ink very readily in the
shadows, but parted with it again very unwillingly. Thence they concluded
that, in order to be able to transfer much ink to the paper, a surplus
of ink must be imparted to the shadows; they thus corrected the tone
values by deepening the shadows, and contended that they produced their
beautiful transfers in this way. I have never seen an English transfer,
but plenty of the French, which were said to have been prepared in this
way. From my own experiments extending over a long period, I doubt
whether the depth in the shadows could be attained in this way, and can
only assume that very important particulars have not been made known in
the excellent publications on this process. A simple reasoning, without
any trial, also leads to the same conclusion. If, for instance, I overink
the shadows by imparting to them more ink than the tone values require,
then I smother all the details in them and in the transfer I shall obtain
a black, absolutely detailless patch. The English and French contend,
however, that all details, which are made invisible by overinking the
bromoil print, become visible again in the transfer. They thus explain
the matter approximately as if we were dealing with a carbon print,
in which the whole film is “reversed” during the development. This is
absurd. A _moderate_ overinking will obviously give better shadows, but
this limitation is of no advantage.
For an important advance in the direction of the production of vigorous
shadows in the transfer we are indebted to the work of Hanns Benndorf,
which was described in an article, “The Technique of the Bromoil Transfer
Process” (_Phot. Rundschau_, 1914, Heft 9, 10). He used the method of
printing in superposition common to all gum printers, since he first
pigmented the original print in a normal manner but with weaker shadows,
printed it and then inked up a second time, treating this time merely
the shadow parts which were to be strengthened, and then printed it on
the first transfer. The results were actually very good. But the process
still required considerable dexterity; its chief difficulties appear to
me to lie in the fact that in the second pigmenting it is uncommonly
difficult to so bring out the shadows that they do not appear too deep
in the final print, and the middle tones and high lights are thus out of
tone. The process is very suitable for bringing out individual parts of
the shadows.
On the other hand a considerable advance in the development of the
process was made by Dr. Emil Mayer, and this consisted of giving to the
bromide print by exposure and development a particular character only
suitable for this purpose. Fuller details of this are given under the
heading “Combination Transfer with one Print Plate,” page 125.
In most publications on bromoil transfer, directions are finally given to
pass the finished bromoil print quickly _once_ through the machine with
a _heavy_ pressure of the rolls, and at the most _twice_. This advice
has received my special attention, because I found that in this way good
as well as bad transfers could be obtained; but I decidedly could not
count on _always_ obtaining equally good results. I noticed that things
went well when I had a pressure on the rolls which was suitable for
the bromoil print and the structure of the paper. Getting this correct
pressure was pure luck. If the pressure was too great, then I indeed got
all the ink on the paper, but the shadows were wanting in detail and
flat; if on the other hand it was too weak, the shadows remained much too
grey.
Hence I came to the idea of so adjusting the rolls that I printed at
first with only a light pressure. I then had as a result a transfer which
was absolutely white in the highest lights, yet showed all the gradations
of the bromoil print in the high lights as well as in the finest and fine
half-tones. The shadows, on the other hand, were grey and not filled up,
for much of their ink still remained on the bromoil print. Then I again
inked the same bromoil print and printed again as before, but did not
take the paper from the machine, observing the transfer by carefully
lifting the bromoil print. It was exactly as described above. Now I
allowed the paper (the lower part of which was still held by the rollers,
further details of which will be found in the section “Printing”) to
again come into contact with the bromoil print, screwed down the central
spindle to increase the pressure, and passed the pack again through the
machine. The result was highly satisfactory. The highest and the high
lights, as well as the half-tones, remained as they appeared at the first
pull, but the shadows were fully filled up and completely transferred
from the bromoil print to the paper.
Thus I had discovered _the principle of printing with increasing pressure
of the rolls_. Further experiments led me to improve the method, and the
following instructions give all necessary explanations and directions.
I must remark that from the start I used a machine the arrangement of
which permitted me to see the print during the printing, and with which
the pressure on the rollers could be regulated at will.
The transfer is not only a step toward the greater development of
the bromoil print, it is so beautiful in its results that no other
photographic process, with the exception of gum printing, at all
approaches it. By the transfer process, photography has made its first
entry into the ranks of the graphic arts. No positive process, other
than bromoil transfer and gum printing, has overcome the oft-bewailed
shortcoming of photography, that there is no sun in the picture, as
well as these two processes. _It is even possible in them to use as the
highest light the pure white of the paper._ In this respect transfer
still has the advantage of offering a more rapid if not an easier
technique.
Certainly the ordinary bromoil print also gives excellent results. Its
whites are, however, formed by the photographic film, and this is its
only disadvantage. There is, however, always a difference of beauty
between a bromoil print and its transfer, the appreciation of which is
purely subjective. We can accept it as certain that feeling in a picture
printed in bromoil is attainable by simpler means than in the more
difficult transfer. The photographic artist will decide for the one or
the other according to the results desired.
THE BROMOIL PRINT.—_For every transfer there must be a bromoil print,
complete in every part._ That is an indispensable requirement for those
who desire to practise transfer.
That a perfect bromoil print can only be prepared from a perfect bromide
print is generally known. It is not my province to describe both
processes fully, for that was long since done by various writers in
excellent works. But it is my duty to give some hints as to the way in
which the bromoil print should be prepared in order to obtain the best
possible results by my new printing technique, which will later be fully
described.
The transfer printer must always keep in view the fact that he must
prepare the way for his final _artistic results_ in all previous phases
of the technical preparation of his print. He will, for this reason,
in a careful and well planned working up of the negative, bring out
the characteristics and feeling of his ideal result by toning down or
suppression of such parts of the picture as may be necessary, a task
which has nothing in common with the process generally called retouching.
He will also make the bromide print, whether by contact or enlarging,
with greater deliberation and care than is used in most cases. Too much
reliance in this respect is often placed on the omnipotent technique of
bromoil, which allows us to carry out the most far-reaching alterations
on the print. This can certainly be done; but perhaps this way is even
more difficult than taking every necessary precaution right from the
start and producing it correctly—in one word: creating it.
Far too little use, for example, is made in enlarging of bolting
cloth, chiffon, or some such open-meshed fabric which, according to
requirements, may be used with wide or narrow mesh, or even doubled,
two pieces in contact [preferably with the threads at an angle of
45°.—Trans.]. Used with discretion, this gives valuable assistance in
producing an artistic softening of contours and contrasts. The same
purpose is attained in perhaps even greater perfection, by using the
procedure recommended by L. Vernouille of Vienna. In this method of
enlarging _two sheets of tissue paper_, of the size of the enlargement,
are laid upon the film side of the bromide paper, and the exposure
is made through these two sheets. It is important that the time of
exposure be exactly determined; this is about double that of the usual
enlargement. The tissue paper must be perfectly white and free from
imperfections, black specks and folds, etc.
Besides these tricks a slight want of sharpness may be used to give the
desired effect, or also the interposition of ruled screens between the
film and the negative.
If it is desired that the bromoil transfer shall show a canvas effect
similar to that of oil paintings, the simplest procedure is as follows. A
piece of cloth is cut from a material which has the necessary structure,
_slightly_ larger than the size of the print, and laid flat on a stiff
support such as pressboard. Then a new piece of carbon paper, such as is
used in typewriting, as thin and free from faults as possible, is cut to
the same size, immersed in water, allowed to drain, and placed smoothly
on the material; a second sheet of pressboard is then placed on top and
the whole subjected to a strong pressure, say between the rollers of a
burnishing machine or washing mangle; if one has not these, then in a
copying press. The carbon paper shows when dry the perfect structure of
the material. If this structure paper is now placed between the paper
and the negative, or in enlarging in contact with the paper, the bromide
print shows this structure together with a very plastic rounded image,
and a longer exposure is not necessary. I consider this procedure better
than the use of the commercial structure screens, since one is free
in the choice of the material from fine lawn to the coarsest canvas,
while among the commercial articles there is seldom one which is quite
satisfactory, and of course no such variety.
The final size of the picture must be drawn on the bromide print in
pencil before the bleaching, for the positions of the edges cannot be
determined on the bleached-out print, especially when the bleaching is
complete. After the bleaching and drying are finished, the pencil marks
should be cut through with a sharp knife on a glass plate, and the print
is thus given the desired size. From this point on, one should be most
careful not to touch the print with the fingers, except on the back,
which can be easily done with a little care, by always lifting up the
edge with a knife.
It is immaterial what bromide paper is used. It may have any surface,
be thick or thin, though thick paper is to be preferred. For prints and
transfers which should show the greatest possible fineness and modeling,
it is better to choose a smooth bromide paper.
The prepared print is swollen and pigmented as in making an ordinary
bromoil print. _It is not necessary, when planning to make a transfer, to
produce a higher relief by a warm water or ammonia bath_, which requires
the use of softer inks and limits artistic freedom in working up. One’s
whole attention must be focused on a _single point_: the shadows must be
_clean_, the lights _pure white_. If this condition be neglected a good
transfer cannot be expected. Deviations from this fundamental requirement
are only permissible for those who have absolutely mastered the printing
technique, and who, therefore, can foresee the results with certainty.
One must take into account the fact that the transfer process has a very
marked tendency to lower the tones. The high lights and fine half-tones
always appear somewhat darker in the transfer than in the bromoil print,
while the shadows, with _correct printing_, remain the same. It is,
therefore, absolutely necessary to lighten up the high lights and the
fine half-tones just as much as they lose in brilliancy in the transfer.
Obviously no description is of any value on this point; a few experiments
made for this purpose will quickly put one on the right track.
The fact that the bromoil print is _trimmed_ before being placed on the
pad has caused some nervous souls to be afraid that water may thus come
from the support through the brush on to the film, but this is not likely
to occur. The pad should be arranged by first laying on the glass plate
a thoroughly wet copying sheet; on top of this a second sheet is laid,
equally wet and with no air-bubbles between. The water is completely
dried off the surface of the second sheet with the aid of a sheet of
lintless blotting paper, and then one can work all day long even in
summer in the greatest heat without changing the support; there will
always be enough moisture to produce adhesion between the sheet and the
support, but one will never carry a drop of water on to the print with
the brush.
THE CHOICE OF THE PAPER.—The pigmented gelatine film gives up its ink
when it is brought into contact with paper under pressure; from which
it seems that theoretically paper of any quality may be used for the
transfer. In practice the matter is not quite so simple, for every paper
surface possesses an individual character which definitely influences the
ink transfer and the final result.
Papers may be roughly classified as rough, medium and smooth, obviously
with many intermediate grades, each of which may be divided into sized,
half-sized and unsized sorts. Whether a rough, medium or smooth structure
is to be chosen, must be decided from a purely artistic point of view,
and in this decision the character of the subject and the effect desired
are of equal importance. It is different, however, as regards _sizing_.
The quality of the picture frequently depends on a correct decision on
this point. This is at once clear when we consider that unsized paper
is much more porous than half-sized or fully-sized paper, and thus can
remove the ink much faster and more completely from the bromoil print.
If, for example, a bromoil is transferred with a certain roll pressure
on copper-plate paper, that is, on a very absorbent porous paper, the
ink will be quickly transferred to it, whereas a sized paper, under the
same conditions, that is, with the same pressure on the rolls, will take
up only a small part of the ink. A comparison of the two transfers would
then show that the shadows on the copper-plate paper are blocked up and
have lost many details, while those on the sized paper appear much too
light, which is readily understood, as the porous paper has taken up all
the ink, the sized paper merely a portion of it.
How far these properties of papers can be equalized or used will be dealt
with in the section on “Printing.”
In choosing the paper destined for the transfer, therefore, attention
not only has to be paid to the structure, which must serve the artistic
purpose, but one must be certain of the amount of sizing; this latter is
necessary so that one may correctly carry out the actual printing process.
As a basic principle the worker should use only _pure rag paper_ and
avoid all paper containing _wood pulp_. Although theoretically it
cannot be disputed that any paper is suitable for transfer, it is also
practically accepted and undoubtedly correct that _beautiful prints_ can
only be prepared on _good papers_, and the artistic photographer should
not be induced by any consideration to use other than the best materials.
All the commercial drawing and water-color papers of all tints and
structure, made by reliable firms, can be recommended. Extraordinarily
fine results are obtained on copper-plate printing paper, which may be
obtained in white and yellowish tints. Equally as good, and specially
suitable for certain effects, are the Japanese and Chinese papers.
The stock of paper should be kept in a dry place and free from dust.
Printing should only be effected on _dry_ paper. Damp paper is used when
it is _very coarse-grained_ and rough, as then the ink is more easily
taken in the depressions. Such sheets are best dampened by immersing them
for some minutes in water, allowing to drain and passing them through the
machine between two sheets of calendered lintless blotting paper with
strong pressure; they are then immediately ready for printing.
If one has to deal with very absorbent papers, with which, especially in
the pure whites, there is always danger that in spite of careful printing
the gelatine film may adhere to the surface of the paper and thus spoil
both bromoil print and transfer paper, the paper should be given a slight
sizing. The preparations to be used for this should be those used by the
gum printer: gelatine hardened with alum, chrome alum or formaldehyde.
But these solutions must be applied warm and then the original brightness
of the paper suffers. It is, therefore, more advantageous to use the
_cold_ preliminary coating recommended by von Hübl to prevent the
sinking-in of the platinum-iron solution for platinotype; 2 g (60 gr.)
of rice or wheat starch or arrowroot should be rubbed up with a little
water and added with constant stirring to 100 ccm (3 oz.) of boiling
water. When quite cold the solution should be applied evenly to the paper
with a swab. The application must result in a slight matt gloss on the
paper without any damp places anywhere. When dry it is ready for use. The
longer the paper is kept after this preliminary preparation, the better
it is.
The beginner will be well advised always to use one and the same quality
of paper until he has succeeded in attaining full command of the
printing technique; I have already pointed out that papers of different
surfaces take the ink from the bromoils with different degrees of ease
or difficulty. Similar differences also occur with increase of pressure.
When the operator has once become perfectly familiar with the necessary
adjustments of pressure with _one sort_ of paper, he will be able without
difficulty to estimate the degree of pressure for other papers. At the
start it is advisable to use a good, half-sized moderately rough drawing
or water-color paper.
It may be remarked that transfers may be made on silk or other textile
fabrics as well as on paper. If permanent results are desired, care must
be taken that pure fabrics are chosen, that is, such as are not filled,
as is usually the case with silk. As the fillers are usually metallic
salts, they may easily have a destructive chemical effect on the inks.
THE MACHINE.—In order to obtain a good transfer, a machine is required
which must satisfy to the fullest extent two requirements: the pressure
on the rolls must be capable of being regulated at will before and during
the printing, and one must be in a position to examine the condition of
the print at any time, without danger that the bromoil print and the
transfer paper will shift. By pressure on the rolls is meant the distance
between the two cylinder surfaces.
[Illustration: FIG. 1]
The autographic metal hand press, model A, as supplied by the firm
of Hugo Carmine, Vienna VII, at comparatively reasonable prices with
different lengths of rolls, is almost an ideal machine for our purpose.
It is shown in Fig. 1 and consists, as will be seen, of a massive metal
stand, which may easily be screwed to any table. Through the center goes
the lower roll or printing cylinder, which is prepared of an elastic
material, and this stands at the same height as the two tables seen on
both sides. Above this lower, immovable roll, there is the upper one,
which can be set higher or lower as required by the central spindle, in
the center of which is the wheel. The central spindle is so arranged
that the upper roll can be raised or lowered by screw gears at the right
and left, the arrangement being such that absolutely even pressure is
exerted at the two ends. On the right screw gear there is a notch in the
form of an I, which with every half revolution of the central spindle
moves the length of one tooth forwards or backwards, according to the
direction chosen, so that it is always possible to produce an absolutely
determinable pressure. The rolls, after the setting of the pressure, are
rotated by the handle visible on the right.
This is the whole machine. Its dimensions are determined by the length of
the rolls, and these are chosen as may be needed. One with 40 cm (16 in.)
rolls ought to be sufficient for most work.
It may be possible to rig up existing burnishers or washing mangles.
Whether good results can be obtained therewith, I cannot say from my own
experience.
The care of the machine is very simple; it needs only to be oiled from
time to time.
Although this, or any other suitable machine, is so simple in
construction, and its manipulation is so easy, yet one ought not to
forget that he who uses it ought _not_ to be a machine. The printer must
be very familiar with his press, if it is to give its best. Whoever does
not believe this should ask an etcher, who will soon tell him how much a
good printer can add to a copper-plate print.
PRINTING.—In order to obtain from any bromoil print one or more pulls on
uncoated paper, one requires, besides a printing machine, also—experience.
Before I proceed with the technical description of the whole process it
will be as well that we become perfectly clear as to the conditions under
which transfer takes place.
Bromoil printing has been described as a direct derivative of the
collotype process, and it is. This very close relationship, however,
is merely because of the common property of the exposed and swollen
chromated gelatine film, but does not extend to the method of execution,
in which bromoil printing displays an independent technique. The primary
difference lies in the support: collotype uses a glass plate as the
support for the chromated image, bromoil printing uses paper. This
causes a variation in the subsequent procedure, especially when the
bromoil print is not the final result, but merely the means for making
the transfer. The application of the ink to the swollen gelatine also is
quite different in collotype and bromoil printing, and the transfer of
the ink to the paper by means of a machine is done differently, all of
which are based on the differences of the support.
The bromide print, which is taken as the starting point in bromoil
printing, should be made on a paper as dense in structure as possible;
thick paper, therefore, is advisable, because the film remains damp
longer during the work of pigmenting, and also because all subsequent
manipulations are carried out more easily with thick than with thin
papers. In the collotype process, on the other hand, the chromated film
is carried on glass. When it comes to printing, it is clear, from what
has been said, that the bromoil print not only contains the moisture
which is absolutely necessary in making it, but also that which is in
the fibers of the paper. The whole of this dampness is pressed out of
the paper fibers and the film, during the printing, and combines with
the ink to a kind of emulsion. This _emulsion-like mass_ is brought on
to the paper by the machine, _not the ink alone_, as in collotype, the
chromated film of which holds only that moisture which is requisite for
its swelling, while its support, the glass, can retain no moisture. It
is also the fact that the amount of moisture in the collotype film is so
small that the formation of this emulsion practically does not occur.
From these comparisons and explanations it also follows that the printing
technique of the two processes must differ.
I have dealt with these facts with more completeness because it is
commonly assumed that the printing of a bromoil print must be carried
out like that of a collotype print, and most of the failures result from
ignorance of the differences discussed.
So, while the collotype matrix only gives up its _ink_, the bromoil
matrix gives up a mixture of _ink and water_ to the paper. This emulsion
is so constituted that it readily adheres to the paper where it is in the
finest state of division, but where it is thicker it is more difficult
to made it adhere. In other words: the high lights and the most delicate
and medium half-tones readily transfer to the paper under light pressure,
while darker half-tones and the shadows must receive a stronger pressure,
from which it again follows, that in order to obtain from a bromoil print
a transfer equally good in all its tones, _I must print with gradually
increasing pressure_.
That is the reason that induced me to use a machine, with roll pressure
which can be varied at will, as I have described more fully in the
chapter on “The Machine.”
The procedure in printing must now be very accurately described, and
takes place as follows:
The pressure which the rolls exert on the bromoil print and the paper
as they pass through must be absolutely even, at every point. In order
to make the pressure more uniform than the rolls of even a good machine
can give alone, it is necessary to imbed the print and the paper in
a press-pack. This press-pack generally consists of two pressboards
(hard, thick, glazed pasteboard), at the bottom, an ordinary pasteboard,
a copper-plate blanket, that is a thick felt, and another ordinary
pasteboard. On this pasteboard the bromoil print is laid, and on this
the printing paper. On this printing paper there are now placed in
order another copper-plate blanket, an ordinary pasteboard and finally
two pressboards. Before, however, we pass a press-pack, thus prepared,
through the rolls, it must be explained in fuller detail, which is best
done from an actual example.
Let us assume that we have a print prepared as described in the chapter
“Bromoil Printing,” ready for transfer. Its size shall be 16 × 21 cm (6¼
× 8¼ in.). Our intention is to print this on paper of the dimensions of
30 × 40 cm (12½ × 16½ in.), and to surround it with a plate mark. As the
size of the paper is 30 × 40 cm (12½ × 16½ in.), the four pressboards,
the three ordinary pasteboards and the two copper-plate blankets should
be cut exactly 32 × 42 cm.
The two pressboards are accurately superposed on a table and then the
pasteboard and the blanket are placed on top. On the last, as already
stated, another pasteboard is placed, which must, however, be previously
marked with pencil guide lines, for on it are to be laid the bromoil,
the paper and the plate-mark pattern. As we wish to surround the print,
which is 16 × 21 cm, with a plate-sunk mark, we must cut a sufficiently
large pressboard to impress this mark. Let us say we wish to surround our
vertical print with a margin which shall be 1 cm (⅜ in.) wide above and
right and left, but 2 cm (¾ in.) below, then we must cut the pressboard
18 × 24 cm (7½ × 9½ in.). When we have done this we mark on it with a
pencil exactly the position of the 16 × 21 cm bromoil print. Now we find
on the 32 × 42 cm pasteboard the position at which we wish to have the 18
× 24 cm pressboard just cut (as a rule this will be a little above the
center), and fasten it there very lightly with library paste or mucilage.
The 18 × 24 cm pressboard now lies on the 32 × 42 cm pasteboard. As the
size of the paper is only 30 × 40 cm, this will leave a margin of 1 cm
on all sides, and this future position of the paper should be accurately
marked with the pencil on the pasteboard. Extreme care having been taken
that all the lines are parallel and the measurements correct, we can now
place in the press-pack the bromide print and the transfer paper, and
proceed to print.
[Illustration: FIG. 2
A = pasteboard
B = the plate-mark pattern
C = the location guides for the transfer paper
D = the location guides for the bromoil print.]
The marking of the individual layers may be done very simply and
accurately if it is carried out as shown in the accompanying diagram.
This marking of the layers has also the advantage that we may use it for
all sizes with slight alterations for individual cases. The lay-out is
very easy. The pasteboard which carries the plate-mark pattern is cut
accurately right-angled and must be about 2 cm (¾ in.) larger all around
than the transfer paper that is to be used. On this board we now draw,
exactly 2 cm below the upper edge, a sharp line with ink that will not
smear, such as waterproof drawing ink, stopping exactly also 2 cm from
each edge. Then this line is bisected and the center point marked zero;
right and left of this zero point we now draw equally distant upright
lines, about ½ cm (³⁄₁₆ in.) apart, which are numbered 1, 2, 3, ... to
the ends of the line. Like divisions are drawn on the plate-mark pattern,
or if this is not to be used, at the place it should occupy. The bromoil
and the transfer paper are now laid down with the help of these lines so
that the upper corners are equidistant from the zero point, which can
be very easily done. These location guides are also very convenient in
combination printing.
We now have lying in front of us one on top of each other: two
pressboards, an ordinary pasteboard, the copper-plate blanket and the
pasteboard with the plate-mark pattern and the marks for locating the
paper.
Now the bromoil print is lifted from its pad by passing a knife under
its edges, and laid carefully with its _back_ on the worker’s left hand.
Thus the print can be laid down face up _without danger of damage_ on the
plate-mark pattern, adjusting it by the position guide before sliding
out the hand, all without touching the face of the print. Great care
must be taken that the print lies absolutely flat. It will adhere to
the pasteboard without any aid except its own moisture. Now we take the
printing paper, hold it at the upper third of its surface with the two
hands and bring the upper edge to coincide with the pencil lines on the
pasteboard which carries the plate-mark pattern, taking care that it does
not touch this pasteboard. When the edge of the paper and the pencil
lines coincide, the paper is carefully allowed to drop into position from
the top to the bottom. It now lies on the bromoil print; now, holding
it _very gently_ on the bromoil print with one hand, the previously
prepared copper-plate blanket is spread out with the other hand over
the paper and pasteboard, and the two pressboards are placed on the
cloth in the same way. Care should be taken that the whole arrangement
is fairly evenly made up, so that none of the edges of the boards or
blankets project beyond others. If this precaution be omitted it may
happen that the transfer paper is squeezed into wrinkles running from the
edges to the middle, which may even encroach on the print itself. These
squeezed-in wrinkles, which, if the pressure be great, may appear like
sharp cracks, make the print useless. This whole manipulation is rather
difficult to perform at first, but it is learnt very rapidly, especially
if the first experiments are made with a damp sheet of paper the size
of the bromoil print instead of the print itself, and one thus becomes
expert.
When the press-pack has been made up in the above-described manner,
it should be taken firmly in both hands, so that nothing can shift,
and the upper edge placed on the machine table and guided between the
rollers, the separation of which must be such that they just grip the
pack _without exerting any pressure_. This separation must be determined
by experiment. The pack should then be gently drawn through until about
4 cm (1½ in.) of its lower edge remains protruding. Shifting is then no
longer possible. The rolls should now be tightened, for which purpose
the central spindle should be given six to eight _half_ revolutions.
The exact pressure cannot be prescribed, but it will always be better
to begin with light pressure. The handle is again turned and the pack
drawn through the press, until its upper edge sticks out about 4 cm (1½
in.). This process is repeated four times—twice in each direction.
If, after the fourth revolution, we carefully lift up the upper layers
including the paper—obviously while the lower edge is still held fast
for about 4 cm by the rolls—we can inspect the _first impression_ and
will see that the high lights and fine half-tones have already given up
all their ink, while the deeper tones still look very flat. The paper
should be allowed to drop back again gently, and then the other layers.
Then the pressure is increased by giving the central spindle about three
or four half-turns, as, after the first impression, there is little
danger to either bromoil or transfer through heavier pressure, and the
pack is again passed through the rolls, but only twice, once in each
direction. If the print is now examined again it will be found that the
full half-tones and the lighter shadows are already transferred, but
that the deep shadows do not appear in full tones. Then the printing is
repeated with still greater roll pressure, three or four more half-turns
of the central spindle; again the pack should only go twice through the
rolls. Another examination should now show the print in full vigor in all
its details. If, however, it should happen, especially when using rough
papers, that the shadows do not yet appear quite deep enough, one should
print again twice with increased pressure. All the ink which was on the
bromoil print will now be transferred to the paper; if the printing
was carried out properly the bromoil will look as if it had not been
pigmented at all.
_It should never be forgotten that the rolls ought never to be so
strongly screwed down that they can only be started by great effort; they
must always move easily, and with little muscular effort._ _Repeated
slow_ passage of the press-pack through _moderately tightened rollers_
is always _more advantageous than a single printing under very heavy
pressure_.
Heavy pressure not only endangers the bromoil, since the gelatine film,
especially in the lights, adheres to the paper and tears when removed,
but the transfer also, because the water, pressed out quickly and with
great force, is deposited in the ink in the form of fine globules. After
evaporation, which takes place very quickly, these places show curious,
light, circular or elliptical spots, which produce the general impression
of a picture painted in the pointillist manner—an undesired effect which,
however, may occasionally be satisfactory.
It is very advisable to turn back the central spindle before finally
taking the press-pack out of the machine, as otherwise one may uselessly
and prematurely ruin the components of the press-pack.
The bromoil can be immediately immersed in water and again pigmented—as
was done at first, or with different ink. This process may be repeated
until the paper breaks down, with careful treatment in printing and
suitable stout bromide paper, up to twenty times.
If the pressure of the rolls was too great, then the film shows blisters,
which at first, and if they only appear here and there, are harmless,
even when they occur on important parts of the print. If their number
increases, however, it is better to make a new bromoil.
If the bromoil is to be kept for future work, then it should be allowed
to become bone dry, in order to dissolve off any grease with benzol or
other solvent, exactly as is done with a bromoil print in defatting.
Prints thus treated can be used again after any lapse of time.
This method of printing is proper for either monochrome or polychrome
impressions.
In conclusion the fact may be mentioned—first published in France, I
believe—that bromoil prints, which in the course of making have been
soaked in ammonia water, can be more easily transferred, and that there
is less danger of the bromoil print and the paper sticking together, even
with very strongly absorbent papers.
Robert Demachy has stated that transfers can also be prepared by
removing the ink, not by a press, but with a solvent, such as benzol, by
moistening the paper with this solvent and then bringing it into contact
with the pigmented bromoil. My experiments in this direction could not
be brought to a conclusion, as at the time I undertook them a suitable
solvent was not available. I had only succeeded in determining that
it is very important that the bromoil print should be allowed to dry
thoroughly—from six to eight hours—and that then a less volatile solvent
than benzol, such as heavy benzine, or best of all, gasoline or petroleum
ether, can be used. If the bromoil print is laid on a sheet of paper and
moistened with this, then pressure in a printing frame is sufficient in
order to obtain a transfer. A machine is not required.
The pictures which I have obtained in this way have not been
satisfactory, up to the present time; the cause of the failure obviously
was that I lacked experience as to the necessary degree of moistening and
the duration of contact. As stated, for lack of materials, I was obliged
to discontinue experiments.
COMBINATION TRANSFER.—The process just described permits the transfer
of all that was in the bromide print. If, however, it is a question of
improving the inadequate gradation of a bromide print from a long-scale
negative, we must use other means. Bromide paper has only a limited
scale of tones and therefore cannot reproduce the full modulation of
a negative of full gradation. If the details in the shadows are to be
retained in such a case, then the high lights will appear bare; if
well-modeled high lights are desired, then we risk blocked-up shadows.
This difficulty has been largely overcome by Dr. Emil Mayer, by the
introduction of a combination printing process for bromoil transfer,
of which full details will be found on page 125. He starts from the
above-mentioned fact that bromide paper does not reproduce the whole
scale of tones of the negative, when this is too long, and therefore
divides the tones of the negative into two parts by exposing one bromide
print only for the shadows and the adjacent half-tones, and a second
merely for the high lights and the lighter half-tones. He then transfers
these two constituent prints in superposition and thus obtains the full
gradation of the negative. It is thus possible therefore to lengthen the
scale of tones _of the negative_. If, however, it is merely desired to
extend the scale of tones of _the bromide print_, then it is sufficient
to make the combination transfer from one print only, which must,
however, be prepared in a way differing slightly from the usual.
I will not repeat here the theory of the two kinds of combination
transfer, which may be found in an earlier chapter by Dr. Mayer (page
125), but in giving my own instructions for the practical performance of
the process, I have essentially adhered also to Dr. Mayer’s instructions,
with his full permission.
COMBINATION PRINTING FROM TWO BROMOILS.—It has frequently been pointed
out in the literature of the gum process that the best positive
transparencies may be obtained from a _long-scale_ negative by making
_two_ positives from the one negative and then bringing these two
positives into superposition; for this combination, one positive must be
_fully exposed_ and _developed soft_, the second, on the other hand, kept
_hard_ by a _very short exposure_ and _full development_. If these two
positives are laid film to film, “there is obtained,” as von Hübl wrote
as early as 1898, _in applying this method to gum printing_ (see Eder,
_Das Pigmentverfahren, der Gummi-, Oel- und Bromöldruck_, Halle, 1917),
“a result which often surpasses, in truth and fidelity to the original,
a normal print from the negative. In such a combined print the high
lights are derived from the short, the shadow details from the long-scale
negative; the two images supplement each other and reciprocally increase
the brilliancy. It is also possible to make good defects in the negative
or the printing process.”
This same principle is used in our process, although not exactly as in
gum printing. The process itself is not difficult. It is necessary to
make two perfectly registered bromide prints, which is most easily done
by always placing the printing frame in the same position in filling,
as for instance by fitting the same two sides into a rigid iron angle
fastened on a drawing board, or, in enlarging, by using a right angled
piece of strong, black card glued to the enlarging easel, and fitting the
paper into this angle. I have prepared a simple and absolutely certain
arrangement for securing registering prints by having a beveled-edge
rectangle cut out of sheet iron 2 mm (⅟₁₈ in.) thick, the opening being
somewhat smaller than the bromide paper. Thus, for instance, for 24 × 30
cm (9½ × 12 in.) paper, the cut-out is only 23 × 29 cm (9⅟₁₆ × 11⅜ in.).
_Care must be taken in this work, however, that the bromide paper for
both prints is taken from the same packet_, since only identical papers
expand absolutely equally in the baths and contract equally in drying.
Although the paper used by the manufacturer may be of the same quality,
yet it may not always be handled exactly the same in coating, so that
a registration of the prints may not be possible when one uses paper
prepared at different times.
The _first_ print is now _very fully_ exposed and developed soft, just
long enough so that the high lights and upper half-tones are well brought
out. When this is attained, development is stopped _without paying
attention to the shadows_, which will be full of detail, but weak.
The second print is exposed as briefly as is required for the perfect
reproduction of the shadows, with the use of a hard-working developer.
As soon as the shadows appear in full depth, the print should be rinsed
and fixed. The print then shows, besides the shadows, only the transition
into the half-tones. It is not easy to give more accurate instructions
for the preparation of the bromide prints, as the work must be carried
out differently according to the negative. Only, _as a hint_, and nothing
more, it may be stated that in a print where exposure of about twelve
seconds was required for the complete printing of the high lights and
half-tones, the shadow print needed only about three seconds, or about
one-fourth the exposure. This ratio obviously alters in accordance with
the depth and quality of the shadows in the negative, and must be left to
the feeling and experience of the worker. When the two prints have been
developed, fixed, washed and dried, they should be tested for equality
of size by measurement with a millimeter scale. Then rule pencil lines
around the edges of the prints very exactly, and treat them in the usual
way in the bleaching bath, the second fixing and washing. When thoroughly
dry the pictures should be cut along the pencil lines with absolute
accuracy, and their registration again tested. It is advisable to write
on the back before bleaching “high light print” and “shadow print.”
Pigmenting is effected as usual. Practically, one should always begin
with the _high light print_, as this is intended to give the finest
modeling in the high lights and half-tones, while the shadows are
treated so that they show all the details, but no depth. This order of
working leaves one absolutely free in the treatment of the fine tones,
independent of the depth of the shadows. These depths are produced in
the transfer in any desired strength by means of the second bromoil. If,
however, the work is started in the reverse way, by printing the shadows
first, then the half-tones and high lights must be adjusted to the
existing depth, which may produce a dislocation of the tone values, even
to a destruction of the whole desired effect. The best way is therefore
to direct the whole attention in the first place to the lighter parts of
the picture, and to suit the shadows to these.
When the _high light print_ is completed as desired, the transfer may be
made. The bromoil print is placed on the location guides, described in
the previous chapter on “Printing.” Then the transfer paper is placed
on its guide and pencil lines very carefully drawn across the edges of
the back, on to the pasteboard. Then it is printed. The picture will now
appear in full beauty as regards the lighter tones, but obviously as a
whole will be flat, since the shadows are grey and without depth.
Now we proceed to the working up of the shadow print, which when complete
should appear absolutely bare of high lights and _light_ half-tones. No
protective measures to prevent the sticking of the non-pigmented parts
to the transfer paper are necessary, as these white portions of the
shadow print are already covered from the first transfer. The print is
now placed exactly on the marks made on the plate-mark pattern before the
first transfer, the first transfer also brought into the same position by
the marks on its back and their prolongations, which is very simple in
practice, and is then printed. The transfer now shows the full gradation
of the negative, or the sum of the gradations of the two bromide prints,
which, however, will be enhanced in effect by the plastic softness
produced by the double printing. If it should be necessary to strengthen
any part of the print, to deepen any shadow, we can again pigment the
necessary portion of the proper bromoil and transfer it to the picture by
a third printing, for it is thoroughly practicable to superimpose as many
impressions as may appear necessary from an artistic standpoint.
This method of combination printing from two bromoils is the best
attainable result in the present state of the art, but contains also the
germ of future developments, especially as regards color photography,
which problem appears to me to be most easily solvable in this, purely
artistic, way. Only it is necessary to find an artist who can conduct the
various printings with such fine color sense that the final result will
actually produce the impression of a _work of art_ in color, not that of
a colored photograph, which has unfortunately hitherto been the case with
all experiments in this direction. This is obviously nothing more than a
hope for the future. For the present we must content ourselves with what
has actually been attained, which is no more and no less than to bring
us close to our aim, ability to consider and use the photographic plate
merely as a foundation for our graphic art.
COMBINATION PRINTING WITH ONE BROMOIL.—It is frequently not easy to
reproduce perfectly in the transfer the whole scale of tones present in
a given bromide print; or at least in many cases a high degree of skill
must be employed. It is consequently often very much simpler to make _two
transfers_ from the _same_ bromoil, one being inked up for the light
parts, while the other is used to fill out and deepen the shadows.
The practical execution of the process is as follows: the bromide print
is swollen in the normal way and pigmented with a _soft ink_ suitable
for the high lights, the shadows being very lightly inked. The transfer
obtained from this bromoil print shows all the details in the high
lights, with grey shadows. The print is now immersed in cold water to
swell again and then inked up with a _hard ink_, so that only the shadows
and the adjacent half-tones are fully worked up. This print is now
transferred to the same paper, so that a transfer is obtained in which
the scale of tones of the bromide print is considerably lengthened.
A second method of making two transfers from one bromoil is first to
swell it normally, then ink up thoroughly and transfer. It is then highly
swollen with ammonia and the shadows only treated with hard ink. The
result of the second transfer on the first one is again full gradation
in the print. This method, however, is not very advisable, as the print
cannot be used again if the second transfer is not successful. It is
better to adhere to the first method, and preferable to use two inks of
different consistency rather than two differing degrees of relief.
If, however, the combination transfer from a single bromoil is to give
the best possible gradation, the exposure and development of the bromide
print must be properly done, the process being essentially that of
Benndorf, referred to on page 143.
The bromide print must be fully exposed and developed very soft; the
image then seems flat, and yet every gradation of tone present in the
negative is actually shown in the bromide print. If a print thus prepared
is treated with inks of two consistencies, the best results are obtained.
THE VALUE OF COMBINATION PRINTING.—With the aid of combination transfer
it is possible to solve problems in the bromoil printing process, which
were hitherto unsolvable, and Dr. Mayer correctly remarks at the end of
his treatise: “The transfer process has advanced to the first place and
in future in the hands of the expert, bromoil printing is likely to be
considered as a process of secondary importance.”
I was early convinced that transfer would replace bromoil printing and am
absolutely of the opinion that combination transfer will do its share in
making my opinion universal. Still I do not believe that it is necessary
to use combination printing in all cases. I would especially warn the
beginner against using it exclusively; he should rather endeavor to make
simple transfers starting from a perfect bromide and a perfect bromoil
print, for by this means he will attain much more certainty in printing
technique. Only when he has absolutely mastered this technique, should
he begin experiments in combination transfer from one bromoil.
_Every worker should endeavor to use the technique of combination
transfer for the execution of an artistic idea, rather than for
overcoming technical difficulties in single transfer._
Then it will, however, always give excellent results. Aside from the
solution of such problems as views from a dark space into a brilliantly
lighted distance, or pictures of falling water in conjunction with its
dark surroundings, etc., it will be especially useful to the portraitist
in treating his backgrounds.
Combination transfer from two originals will, however, be most valuable
artistically, when there is a question of combining sharply defined parts
of a picture with softer parts. Thus, for instance in a landscape, we
may make a sharp print and, by the use of bolting cloth, one with soft
outlines; the parts which it is desired to emphasize will be worked up on
the former and artistic softening added from the latter.
Briefly, the possibilities are so many that they can hardly be indicated,
not to speak of describing them in full. This is, besides, hardly
necessary, for the worker who has reached full mastery of combination
transfer is necessarily so far advanced artistically, that he will find
out for himself all that is necessary.
RETOUCHING AND WORKING UP.—A good bromide print can only be prepared from
a good negative. So says the expert bromide printer. The bromoil printer
_requires_ a faultless bromide print as the fundamental condition.
The transferrer, finally, will not use an imperfect bromoil print for
transfer.
I belong to the school which would produce a photographic picture only
by purely photographic means, without, however, being too orthodox; I
would not, therefore, repeat the whole laborious making of a bromoil
print, because I might not think it photographic to spot out with
water-color a small spot the size of a pin’s head, or to remove a small
particle of ink with the etching knife. This is actually not retouching,
but there are people who consider these changes as such.
By retouching I mean the justly condemned excessive “working up” of a
_positive_ print, that is a change of values on the finished print. That
should not be done.
Bromoil printing is still that exquisite process which permits the
correction of false tones, the suppression of undesirable and the
emphasis of the most characteristic details in the most extensive way
_during the work_.
I consider it objectionable to leave all faults which occur during
the long process of picture making, for the sake of convenience, to
be improved on the positive print. But if it does become necessary to
use retouching on the transfer, it can be done with a soft eraser. An
excellent means of working up larger areas has been described by Dr.
Mayer (see page 123), which consists in working on the transfer with
the same brush and the same ink as was used in making the bromoil. Thus
clouds may be imitated by pigmenting the white surface and then working
in the clouds with the eraser, etc.
Since, however, this and other improvements can be carried out, not only
as well, but even better on the bromoil print itself, it is advisable to
do so much with the brush that nothing remains to be done on the transfer.
DRYING.—As soon as the transfer leaves the press, it is finished, but as
the ink is very easily smeared it is advisable to leave it exposed to
the air for two or three days. After the lapse of this time the ink has
usually hardened.
Very heavily inked prints require from eight to ten days to dry and may
be considered as absolutely dry when the oily sheen which can be seen
immediately after printing, especially in the shadows saturated with ink,
is replaced by a velvety, perfectly matt surface.
Retouching can be begun about one or two hours after it has left the
machine.
A transfer should not be mounted, for it looks best as it is, if the
margin is sufficiently large.
CONCLUSION.—The technical difficulties of making a good transfer are
not small, and to overcome them requires a certain degree of skill in
the worker, which other processes do not require to an equal degree. By
“workers” I mean especially amateurs, not those professionally skilled
in the graphic arts. After overcoming these difficulties, caused chiefly
by the materials, there is a certain feeling of satisfaction in having
actually produced a work of art. By using the different techniques
of bromoil printing: soft ink, hard ink, sketch, and coarse grain,
one can obtain transfers of such beauty as may confidently be said
can be attained by no other process. There is unlimited possibility
of variation; and this alone assures the bromoil transfer process
preëminence over any other method of printing.
That a transfer can be used as a basis for working up with pastel and
water-color need only be incidentally mentioned, because such work
is outside of pure photography and it is unnecessary to express an
opinion as to the artistic value of such productions in this place. The
photographer should always adhere to the fundamental law: Do not forsake
photographic methods.
CHAPTER VIII
THE PREPARATION OF BROMOIL INKS
BY EUGEN GUTTMANN
Everyone who devotes himself to the higher aims of photography, and
studies the works of painters, must learn to see with the artist’s eye if
he will apply his knowledge in pictorial presentation of his subjects.
In the same way the bromoil printer should become more familiar with
the working tools of the painter, and especially with the most valuable
material at his command, the ink, than has hitherto been the case.
When we look back on the history of painting, we note the often-mentioned
fact that not only the old masters of all schools, Italian, German and
Dutch, but also the later generations till about the middle of the last
century, ground their own colors. They did this not merely to be assured
of the most perfect purity and thus absolute permanency, but also because
they wanted to obtain the greatest possible brilliancy.
As regards the purity of the materials used—the colors and the
mediums—there is no doubt that to-day, thanks to the high perfection of
manufacturing methods, this can usually be depended upon; but as regards
the brilliancy, no positive instructions of any kind for obtaining this
have come down to us. The painters took their secrets with them to the
grave. But as the result of exhaustive research, together with advances
in the manufacture of colors, we can assume with some certainty that
the masters of past times attained _vigor in their colors_ chiefly _by
the finest possible grinding of the colors and by a relatively small
addition of medium_. “_It may sound paradoxical_,” says Professor Th.
Petruscheffsky in one of his treatises on the technique of painting,
“_but it is, however, true, that in oil painting oil should be avoided as
much as possible_.”
The old masters knew this and acted accordingly, and the modern
manufacturer also knows it, and replaces _any excessive quantity_ of oil
in the medium, which is mixed with the pigments to bring them into a
paintable form, by other substances, for instance turpentine, and certain
resin solutions, which have no binding properties; during the work these
substances evaporate and leave behind the color with very little medium.
These facts the bromoil printer must know, for he should also use colors
from which he can get the very best possible results.
The ink is one of the most important parts of his equipment. This fact
was fully recognized by English, French, and German manufacturers, and
inks were obtainable that left nothing to be desired. At the outbreak
of the war the position of affairs was immediately altered. It was not
possible to use English and French sources of supply and the German
supply gradually failed. What was furnished as ink for the oil process
was suitable for anything else but that—a soft, smeary and smearing mess,
which did not permit any finer working up of the picture, and required so
high a relief that individuality in the work was excluded.
These conditions induced me to try and prepare the necessary inks
myself, and after many trials and exhaustive experimental study of the
manufacture of artist oil colors I finally succeeded in reaching my goal.
INKS AND BRUSHES.—My starting point was a great desire to make a _hard
ink_, since I recognized that this consistency was the necessary starting
point to be able to use any degree of relief. I further desired to attain
a mixture of color and medium which should be as perfectly homogeneous
and as fine as possible, and moreover to provide a palette, which should
not only satisfy all requirements of the bromoil printer, but also give
him only fast colors, perfectly suitable for the transfer process and
soluble in benzol.
Command of a _hard ink—which can be suitably softened to meet any
need_—is very necessary to the bromoil printer, if _clean shadows_ are to
be obtained. As already mentioned, it has long been known among painters
that the colors appear purer and more luminous when they contain as
little medium as possible. In order to be able to apply such stiffly
ground colors, the painters use bristle brushes, which do not produce
the same results as hair brushes. Naturally there is nothing to prevent
the bromoil printer from using _bristle brushes_, only they must fulfil
certain requirements. The literature of bromoil printing gives many hints
on this point, but I have not been able to locate a practical use of
these brushes. Some years ago I had made, by a manufacturer who makes
excellent hair brushes for our process, bristle brushes in stag’s foot
shape. The result was extraordinarily gratifying. These brushes do not
drop their bristles nor do they suffer from the troublesome breaking off
of the points, they do not pick up the dust and do not smear even when
very soft inks are used, because the bristles, unlike hairs, do not cling
together. They can be easily and thoroughly cleaned and are obviously
very lasting, and in addition cost only a fraction of what must be paid
for really good hair brushes.
As regards the size one is not limited, as with the hair brushes, to
small sizes, since the hog’s bristle brushes can be made of any desired
diameter, even 10, 15 or 20 cm or more (4, 6 or 8 inches or more) so that
the working up of large prints is considerably facilitated.
Two conditions must, however, be carefully observed for good results.
First, these brushes must actually be made from the _very finest cut_
bristles and, before they are used, they must be _repeatedly and very
thoroughly cleaned_, because they are very dirty when purchased.
The principal advantage of these brushes is that they _enable one to
use considerably harder inks_ than is possible with hair brushes, which
results in _much greater clearness of the shadows_. When this clearness
of the shadows is obtained, one can always use a hair brush for working
up the finer half-tones and high lights. This is, however, not necessary,
at least in the majority of cases.
I have _not_ noticed any disadvantage in the use of these brushes; the
gelatine has never been pierced, even in the highest reliefs.
Although I am averse to anything that may smack of advertising, yet
I will state here the source of these brushes, because the expert
manufacture of these tools, so important in our handicraft, is not found
everywhere in equal perfection, and because I believe that it will be of
considerable service to those wanting brushes. The brush manufacturer is
Magnus Bühler, Wien VII, Breitegasse 4, Austria.
[Illustration: FIG. 3]
I might add a word here as to the cleaning of brushes in general, whether
hair or bristle. It is usually recommended to wash out the ink with
benzol or similar solvent, carbon tetrachloride, trichlorethylene, etc.
A really thorough washing is never obtained with these; and the brushes
almost always give up a greater or lesser quantity of small particles
of ink to the new print when used again. The following process is much
better. The brush to be cleaned should be dipped into lukewarm water and
then rubbed firmly on a piece of ordinary soap (soft soap is better), so
that it takes up as much soap as possible. Then the soap should be worked
up into a lather on the palm of the hand and washed off. If this is
repeated a second time and the brush is then rinsed two or three times
in lukewarm water, repeatedly changed, the brush will be far cleaner
than can be obtained in any other way. After it has been well rinsed and
shaken out it should be put into its tube and hung up by the handle in a
place free from dust to dry (see Fig. 3). This vertical position has the
effect of facilitating the draining of the moisture from the quill base,
where it otherwise collects. Any brush thus treated will be dry in a few
hours. The finest hair brushes are not damaged at all by this treatment,
which is commonly used by painters.
THE PREPARATION OF THE BROMOIL INKS.—The preparation of the bromoil inks
is very simple. The following are necessary:
Linseed oil varnish of the thickest consistency;
Powder colors;
A rubbing plate;
A pestle;
A springy spatula (palette knife);
A stiff spatula, the so-called ink knife (putty knife).
The following sections will give the necessary information as to the
properties and nature of each item in this small arsenal.
THE VARNISH.—Only such varnish should be used as is prepared from linseed
oil and chemically pure. Its color should be light to brownish-yellow
or at most reddish-brown. Dark brown or blackish-brown varnish points
to adulteration. The smell is that of linseed oil and is not exactly
pleasant, but it should not smell badly. In the latter case one may
reckon with certainty on the addition of fish or resinous oil. One
principal requisite of this varnish is that it should be absolutely
_clear_. The varnish is produced of various consistency, from quite
fluid to quite viscous, and _this is one of the principal properties, to
which the bromoil printer must pay special attention, for every degree of
consistency demands and must have only one definite quantity of color_,
otherwise the resultant ink will not satisfy the desired end. More as to
this later.
I used for all my experiments and later for all actual mixing the linseed
oil varnishes, No. 1 and No. 2 (chemically pure) of the firm of Kast &
Ehinger, of Stuttgart, which have always given me excellent results,
without failures. Excellent also is the somewhat less stiff “collotype
varnish.” But any other varnish, if it only has the right consistency and
is not adulterated, must also give good inks, though great care must also
be taken as to clearness and color.
Warning should be made against oils similar to varnish, which can be
recognized by a cloudy appearance and a very unpleasant rancid odor. They
harden very quickly and thus become useless and are very costly.
The stiff varnish is very viscous, like thick syrup. In the cold it
thickens with the formation of a thin skin on the surface. On a hot water
bath, it again obtains its original character. Well corked up, good
varnish will keep for years; it even becomes better by long storage. It
is most convenient to fill the varnish into small wide-mouthed bottles,
holding from 20 to 40 g (about an ounce), with ground-in stoppers, as
one can note its appearance at any time through the glass. In taking
the varnish out of the bottle, care must be taken that none gets on the
inside of the neck, or else the bottle can only be opened with difficulty
through the varnish gumming it up.
POWDER COLORS.—Only such colors should be used as are fast both to light
and air. The following may be selected with absolute certainty:
For black: bone black, ivory black, crayon sauce;
For brown: burnt umber, burnt sienna, burnt dark ochre;
For yellow: cadmium, light and dark, yellow ochre, light and dark;
For red: English red, light and dark, Indian red;
For blue: indigo, ultramarine, cobalt blue;
For green: cobalt green, light and dark, Bohemian and Veronese earth;
For white tones: zinc white.
The bromoil printer obviously does not need all these. One representative
of each group will be quite sufficient, and I should state that when
colors are obtainable in both light and dark shades, the light one should
always be chosen.
The colors must be very finely ground; it will not be necessary, or
only exceptionally, to prepare the powder colors oneself, for they can
be obtained commercially in every high grade store dealing in painters’
materials. If, however, this becomes necessary, then the lumps of color
should be crushed on a stone or glass with a flat muller, and the coarse
granular masses thus formed kneaded with a little water, or, better
still, some alcohol and then thoroughly ground. The mass should be
allowed to dry thoroughly and the process repeated two or three times.
_The finer the powder is rubbed up in this way the finer the tone it will
give._ The _coarse_ color powders, often found in drug stores, are not
suitable for our purpose; they are used more for industrial purposes.
_Aniline_ colors, or those brightened with anilines, should be absolutely
avoided, as they stain the gelatine and thus spoil the print. On the
other hand I call the attention of all bromoil printers to the _pastel
colors_, which can be used with excellent results. They offer many
advantages over the powder colors, since among the hundreds of color
shades, in which they can be obtained, it is easy to choose that which is
most suited for the subject. The tints are ready to use, while with the
powder colors the desired tint can only be obtained by mixtures. These
colors have the further advantage of covering much more strongly, even
to obtaining brush texture; they are somewhat more difficult to apply to
the print, because of the fact that they are mixed with a medium which is
from its nature not so well adapted to our process. Those, however, who
have well mastered the brush technique, will easily overcome this small
hindrance.
If the pastel colors are used one should only take those of reliable
manufacture, such as those made according to Mengs’ formulas, which are
everywhere obtainable under the name of _Meng’s pastel pencils_, though
this does not mean that those of other makes will not give excellent
results.
THE RUBBING PLATE.—For this we use a thick plate glass slab, ground on
one side, about 15 by 20 cm (6 × 8 in.).
PESTLE OR MULLER.—A pestle of glass is the best. The head must be round,
not flattish, and have a matt surface.
SPATULAS.—It is necessary to have a flexible spatula (palette knife)
about 1 cm (⅜ in.) wide and a stiff one, an ink or putty knife, about 4
to 5 cm (1½ to 2 in.) wide.
Now that we have become conversant with all the necessary materials, I
come to the:
PRACTICE OF INK GRINDING.—As I have mentioned above, the purpose of the
work is to obtain an ink of as stiff a character as possible. To this
purpose, after the vessel in which the varnish is kept has been allowed
to stand at least 10 minutes in hot water, or an hour in winter, we
remove from it by means of a wood or glass rod a very small quantity of
the varnish, spread it on a glass plate and rub it with the pestle so
that it covers a surface of 3 to four qcm (½-¾ sq. in.). To the varnish
thus spread out we add with the flexible spatula a small quantity,
about as much as will lie on the end of a pocket knife blade, of the
powder color and rub it with the pestle until certain that the color is
absolutely mixed in. If too little color has been taken, more should be
added and rubbed again until a firm doughy mass is obtained which has a
_slaty and not oily gloss_, and can scarcely be worked with the pestle.
Now with the springy spatula the whole ink mass is pushed together from
the edges to the middle to make a little heap, and the ink that remains
on the pestle scraped off and added to it; the whole mass should then be
again worked up with the pestle and this procedure repeated two or three
times. Then the ink is ready. It must be so hard that a brush set into
a small quantity of the ink that has been taken from the heap with the
stiff spatula and spread out in a thin film, neither takes up the ink nor
gives it up again to white paper. In order to make it fit for use, one
must add to this thin film _one_ small drop, not more, of pure linseed
or poppy oil, petroleum, light copper-plate printing varnish, or medium,
and mix it well with the ink with the stiff spatula. Petroleum can be
highly recommended for the softening medium. One can use the ordinary
lamp petroleum, but the so-called purified petroleum is better. It ought
only to be added to the ink drop by drop. Now the brush will take up and
give up the ink. If it should not be sufficiently soft, the procedure
should be repeated, but always carefully, so that too much linseed oil is
not added and thus the ink made too soft. If we use the pastel instead
of the powder colors it is not necessary to break these up first. Small
pieces broken from the pencils dissolve readily in the varnish. It would
seem permissible to assume that the whole work of dilution with linseed
oil could be saved by not adding so much color to the varnish, but by
proceeding with the inking-up as soon as the ink is taken up by the
brush, _but this is not the case_.
As I have stated above under “Varnish,” every degree of consistency of
the varnish requires a definite quantity of color. If one adds too little
color, the paste will be too soft for bromoil printing, and cannot be
spread. Too much color is hardly possible with the stiffest consistency;
the limit lies when the color no longer dissolves in the varnish. Too
little, on the other hand, results in the ink smearing on the print.
_It is, therefore, absolutely necessary_ in using very thick _varnish_
to _absolutely saturate_ it with color. _Not going far enough in this
direction_, or the omission of the preliminary warming of the varnish,
_are the only sources of failure_. In working with varnish of lighter
consistency, it will be necessary to stop the addition of color as soon
as the slaty gloss appears.
If the grinding of the ink were to require as long as it takes to read
this description, the waste of time would be considerable. Actually the
whole work may be carried out in two or three minutes if one uses the
methods suggested, and after a little experience is gained, which soon
comes after a few trials. Long before the water for the bromoil print is
hot, the ink will be ready.
INK MIXING.—As it is not always possible to use existing colors, and it
is necessary in many cases to alter the shades for artistic effects, the
basic colors must be diluted with other colors. This can be effected in
many ways, best by adding another color to the predominant color powder
during the mixing. _Bone black_ is specially valuable for this purpose.
This is by itself an unpleasant color, for it is a discordant brown-black
which can hardly be used alone. If other colors, however, are added to
this bone black it produces beautiful tones. Thus, for instance, the
addition of a minimum of blue (indigo or ultramarine) gives a _deep,
velvety black_; if a _little_ more blue is added, we obtain a beautiful
blue-black. A little bone black mixed with burnt umber gives a fine _warm
black_, and so on.
The tone of crayon sauce is especially beautiful, if it is used without
the addition of any other color, and especially that quality obtainable
under the name of _Sauce Velours_ is particularly excellent.
Another kind of color mixture is that in which black is taken as _the
fundamental color_ (which is desirable when it is not desired to mix up
ink for each print) and then instead of diluting the _stiff_ ink with
linseed oil or other diluent, an ordinary good copper-plate ink or even
ordinary _oil colors_ are used. By this method of working I can shade
and soften in one operation, and it is highly advisable to use it when
it is desired to obtain different tints easily. The method of mixing is
very important and I will therefore give some examples. If to the stiff
black ink (bone black), I add a little indigo _oil_ color, I have at
once a deep black; the addition of vandyke brown or burnt umber gives a
magnificent brown; a fine dark green is obtained with light cadmium; this
dark green becomes blue-green when I add a little indigo. An admixture
of caput mortuum shows violet tones; red tube colors, such as Indian or
Pompeian red, ochre, etc., give various reddish brown nuances. These
additions can be varied in manifold ways, dependent only on what tube
colors are at hand. It is strictly necessary, however, that only the
least possible quantity of tube color should be added, about as much as
the head of a good-sized pin, to keep the ink from becoming too soft and
going beyond the desired tint. When a suitable shade has been attained,
all further dilution must be effected with linseed oil, petroleum, etc.
When I specially recommended the Mussini or Fiedler colors, it was
because they are prepared with resin oils and are therefore specially
suitable for our purpose. But all other _good_ oil colors can be used.
When I write briefly only _oil colors_, I mean obviously _artists’ oil
colors_, and not others which may be used for other purposes than for
artistic painting.
Finally the black may be diluted with linseed oil to the usable
consistency of hard ink and also diluted on another part of the palette
with oil color or copper-plate ink of another shade to the consistency of
a soft ink, and then both colors may be mixed either on the print or in
the brush.
Very fine gradations may also be produced as follows: the bromoil
print is pigmented as usual to obtain as _clear_ shadows and _clean_
high lights as possible, with not too high a relief. When the print is
completely finished, it should be placed in a 2 per cent cold solution
of ammonia, this allowed to act for two minutes and then rinsed for one
minute in clean water. Then the print, which is considerably swollen,
should be very carefully dried off, so that no ink comes off on the
cloth, and the latter leaves no imprint of its structure. Now the whole
print is gone over with a clean brush, on which is a _very little pure
oil color_. By thus using light, transparent (_lasur_) colors, and
only such ought to be used for this purpose, the print may be given an
extremely delicate film of ink, through which the first image shines with
full vigor. This gives an effect similar to that which the gum printer
obtains by multiple printing.
According to whether the whole or only parts of the print are gone over
with the “lasur” color, the most varied effects are obtained, such as
deepening of the shadows, or lowering of the high lights, or both.
It is naturally impossible to describe this process exactly in print.
Much must be left to artistic feeling, without which hair-raising color
discords will probably be produced. Still, in order to give the beginner
some starting point, it may be mentioned that black, brown or red tones
may be easily treated with inks shaded towards grey, blue with pure grey,
and so on.
The following summary of color mixtures for the beginner is also given:
_red-brown_ is obtained by mixing bone black, Indian red, and possibly
dark alizarin lake; _violet_ results from bone black with red and blue;
_dark green_, from black, cadmium and blue; _brownish-green_, from black
and indigo; _bright green_, from a little black with cadmium and indigo;
_red chalk_, from black, brown and Indian red.
The individual tints will obviously vary considerably, according as more
or less of any given color is taken. This is entirely a matter of taste
and must be left to the judgment of the individual.
When the stiff ink is ready on the glass plate, it is advisable to
carry out all further manipulations on a white porcelain palette or
tile, because the mixtures can be much more easily judged in tone and
consistency on these white supports. The mixtures are best made with the
stiff spatula (putty knife).
PERMANENCY.—The permanency of home-made inks prepared by oneself is
satisfactory if they are preserved from dust and air. My inks have kept
for periods exceeding three months, with the most satisfactory results.
[Illustration: FIG. 4]
INK-GRINDING MACHINES.—For all ordinary purposes the inks prepared in
the manner just described are perfectly satisfactory. For inks, however,
which must be extremely fine this method of mixing is not sufficient,
therefore, I had a small machine constructed (Fig. 4), which consists
of two rollers turning in opposite directions. The hand-ground inks are
placed on these rollers and kneaded with strong pressure for two or three
minutes. The whole machine is 25 cm high and 20 cm wide (10 × 8 in.), and
can be conveniently fastened on the corner of any table. The resultant
inks are of a fineness and quality which have not been bettered by large
manufacturers.
ADDITIONS TO THE INKS.—If it is desired that the inks should dry matt
on the bromoil print, so that the defatting with benzol may be omitted,
then one should add to the home-made inks a small quantity of one of the
following mixtures:
(a) Beeswax 1 g (15 gr.); melt by heat and add with stirring 20 drops of
linseed oil. As it cools a salve-like mass is formed. Or:
(b) 1 g (15 gr.) kieselguhr (infusorial earth) rubbed up with linseed oil
to a quite thin fluid paste.
It should be noted that these mixtures, in consequence of their content
of linseed oil, make the inks softer.
Books on Photography
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PRACTICAL PHOTOGRAPHY SERIES
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7. How to Make Lantern Slides.
8. The Elements of Photography.
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