Tinting and toning of Eastman positive motion picture film : $b Second edition

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Title: Tinting and toning of Eastman positive motion picture film : Second edition—revised
Author: Anonymous
Language: English
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POSITIVE MOTION PICTURE FILM ***

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Tinting and Toning
_of_
Eastman Positive
Motion Picture
Film

Price $2.50
Second Edition—Revised

Eastman Kodak Company
Rochester, N. Y.
1918

PREFACE

Owing to the difficulty of obtaining foreign made dyes, a revision of
the first edition of this publication has been made necessary.

As the result of an exhaustive series of tests of the products of the
National Aniline & Chemical Company, Incorporated, New York City, it
is now possible to recommend a number of American made dyes suitable
for the tinting of motion picture film, and those recommended in this
book are in most cases equal in every respect to those previously
obtained abroad.

To date, it has not been possible to obtain a thoroughly satisfactory
blue dye, film tinted with the Cine Blue recommended being too red,
especially before drying. A more suitable dye will no doubt be
available in due course.

The number of sample tints has been curtailed to twelve, and these
are given merely for guidance. It is intended that the various
formulas should be altered to suit individual requirements.

The chapter on toning has been thoroughly revised, a number of tones
having been eliminated and others substituted. The formula for the
copper tone has been improved, while the formulas for green tones
requiring the use of vanadium chloride have been eliminated in view
of the expense and difficulty of obtaining satisfactory vanadium
chloride. With the samples at present on the market it has not been
possible to prepare a single-solution toning bath which would keep
for any reasonable length of time.

Attention is drawn to the new method of dye toning[1] recently worked
out in our Research Laboratory. This consists in first treating the
film in the copper toning bath and then immersing the washed film in
a solution of a basic dye, the dye attaching itself to the image and
leaving the gelatine clear. Although specific directions are given
for obtaining five tones only by this method, as further dyes are
available, those suitable for toning purposes will be published in
due course.

The method of producing sulphide tones has been changed to one of
simple re-development with sodium sulphide, the addition of hypo to
the sulphide solution having been eliminated. By commencing with thin
positive film of the correct density, and using a plain solution of
sodium sulphide for re-development, satisfactory transparent tones
are obtainable with precision.

The formulas for the iron and uranium tones are the same as in the
first edition.

EASTMAN KODAK COMPANY,
ROCHESTER, N. Y.

August, 1918.

Tinting and Toning of Eastman Positive Motion Picture Film

In the production of motion picture film it is becoming more common
to vary the color of the film either by toning or tinting or by a
combination of the two processes. Toning consists in either wholly
or partially replacing the silver image of the positive film by some
colored compound, the clear portions or highlights of the image,
consisting of plain gelatine, remaining unaffected and colorless.
Tinting, on the other hand, consists of immersing the film in a
solution of dye which colors the gelatine itself, causing the whole
picture on the screen to have a veil of color over it.

PART I.

TINTING

In “tinting” the following factors must be taken into consideration:

Nature of the Dye Employed

Dyes are chemically of two different types, acid and basic; so-called
acid dyes are the alkali salts of organic acids, while basic dyes are
the chlorides, sulphates, etc., of organic bases.

For the tinting of film only “acid” dyes have been considered
since it is not possible to make a complete selection from basic
dyes alone, which would necessitate the use of acid and basic dyes
in admixture—a procedure highly undesirable and in many cases
impossible.

Any dye suitable for admixture with others to produce intermediate
tints should possess the following properties:

_A._ The dye should be inert and not attack the gelatine or support.
This is of fundamental importance as the gelatine coating of dyed
film in many cases has a tendency to lose its flexibility, giving
rise to what is known in the trade as “brittleness.”

Several dyes when employed at a concentration of 1% attack gelatine
readily at 70 degrees F. and vigorously at 80 degrees F., especially
in presence of small amounts of acid, producing a marked softening
and often partial dissolution of the film. The effect is roughly
proportional to the concentration of the dye and to the temperature,
and varies with each individual dye.

Experience has shown that the gelatine coating of film which has
been softened in this way by the dye becomes “brittle” on subsequent
projection.

The actual factors in the production of brittleness are:

1. The hydrolysing action of acid which in many cases is added to
assist dyeing. In case a solid acid is employed the heat encountered
during projection will greatly accelerate this hydrolysis.

2. The corrosive action of the dye itself. Dyes vary considerably in
this respect according to their particular composition. So far, it
has not been possible to make any general classification of dyes in
this connection, though nitro compounds appear to be particularly
corrosive in their action.

3. The presence of impurities in the dye. These take the form of
excessive amounts of loading material such as sodium sulphate or
chloride, or small traces of iron, the latter having a tendency to
harden the film considerably.

In all the above cases, the physical nature of the gelatine is
altered, whereby it loses its property of remaining resilient
under normal conditions of temperature and humidity, resulting in
“brittleness.”

A suitable test as to whether a dye has any propensity to produce
brittleness is to incubate a sample of film, half of which has been
dyed, for about 48 hours at 212 degrees F. If any difference in
brittleness is noticeable between the dyed and the undyed portions
so treated after the film has been allowed to stand in the air for
some time, the dye is unsuitable for tinting.

Apart from the above, most dyes when used at a concentration of 1%
and at 80 degrees F. produce more or less softening of the gelatine,
which may be prevented by:

(a) Use of only dilute solutions. Except in very special cases, a dye
solution stronger than 0.5% is seldom required, the usual strength
employed being about 0.2%, at which concentration softening is
unusual.

(b) Use of a minimum amount of volatile acid in the dye-bath or
omission of the same whenever possible.

(d) By slight hardening of the film before dyeing and subsequent
softening by glycerine, as described below:

_B._ The dye should not “bleed” to any considerable extent when the
film is washed; in other words, the rate of removal of the dye should
be slow and only a slight amount should wash out in a period of, say,
five minutes.

In tinting, bleeding is of very considerable importance, since,
during the periods between rinsing after dyeing and the placing of
the film on the drying rack, any drops of water on the surface of the
film become more or less saturated with dye, and these after drying
remain as spots and irregular markings which are very apparent on the
screen.

It is possible in some cases to modify this bleeding by an acid “stop
bath,” or by adding acid to the dye-bath; though it may be considered
a general rule that the bleeding of a dye is a property peculiar to
itself. In making a selection of dyes therefore, it is necessary to
choose only those whose propensity for bleeding is a minimum.

_C._ The rate of dyeing should be only slightly affected by the
addition of acid to the dye-bath, although most acid dyes are more or
less sensitive to acid.

In case the rate of dyeing is appreciably affected by the addition
of acid it is possible to take advantage of this fact since a much
weaker dye solution may be employed to obtain a given tint, while an
apparently exhausted bath may be revived by adding a small trace of
acid.

Only a volatile acid such as acetic acid should be used since this
will evaporate on drying, while the strength of the acid in the
dye-bath should not exceed .05% or one part in 2000, otherwise
softening of the gelatine is liable to occur, especially if the
temperature exceeds 70° F.

In the case of a bath containing a mixture of dyes, owing to the fact
that acid affects some dyes more than others, as the dye-bath becomes
exhausted and the acid content changes, the tint obtained will
gradually change also. It is only possible therefore to use acid with
any degree of certainty in the case of dye-baths containing a single
dye.

_D._ The dyes should not fade on exposure to heat or light and should
not be “dichroic” or change color on dilution.

_Moreover, the wear and tear of the film should not be impaired in
any way after dyeing, and even after incubating for 48 hours at 212
degrees F., afterwards allowing the film to humidify, no difference
should be discernible between dyed and undyed film so treated._

_E._ The dye should not be affected by the acid fixing bath since any
fixing solution accidentally splashed thereon, would destroy the dye
immediately.

In view of the large number of tints required in commercial work, it
is undesirable to keep a separate dye-powder for the preparation of
each particular bath, but rather to prepare the same by admixture
of three or more dyes. If three only are employed, mixing must be
conducted with great precision in order to reproduce any given tint,
but this difficulty is removed by the use of intermediate colors.

The following six standard dyes have been chosen as fulfilling the
above conditions as nearly as possible, and by suitably mixing
solutions of these, almost any desired tint may be obtained.

Name Used in Formula Commercial Name

Cine Red Serichrome Blue R
” Scarlet Crocein Scarlet MOO
” Orange Orange A Concentrated
” Yellow Niagara Fast Yellow
” Green Ammaco Acid Green L
” Blue Buffalo Fast Blue R

These dyes are obtainable from the National Aniline & Chemical Co.,
Inc., New York City.

The strength of the dyes may vary slightly from batch to batch, but
this variation is usually so small as not to materially affect the
nature of the tint obtained from any particular formula.

The Cine Blue dye appears much redder by artificial light than
by daylight, especially before drying the film, as do all tints
containing Cine Blue.

The following formulas are given merely for guidance and should be
altered to suit individual requirements.

When matching any color view only by artificial light.

FORMULAS FOR TINTING AT 65° F.

Tint Number on Chart Avoirdupois Metric Time of Tinting

1. Cine Red 8 ozs. 250 grams
Acetic Acid (Glacial) 3½ ozs. 100 grams
Water 50 gals. 200 liters 5 minutes

2. Cine Red 8 ozs. 250 grams
Water 50 gals. 200 liters 10 minutes

3. Cine Scarlet 8 ozs. 250 grams
Acetic Acid (Glacial) 3½ ozs. 100 grams
Water 50 gals. 200 liters 5 minutes

4. Cine Orange 8 ozs. 250 grams
Acetic Acid (Glacial) 3½ ozs. 100 grams
Water 50 gals. 200 liters 4 minutes

5. Cine Orange 1 lb. 500 grams
Water 50 gals. 200 liters 10 minutes

6. Cine Yellow 8 ozs. 250 grams
Water 50 gals. 200 liters 10 minutes

7. Cine Yellow 4 ozs. 125 grams
Cine Green 8 ozs. 250 grams
Water 50 gals. 200 liters 10 minutes

8. Cine Green 13 ozs. 400 grams
Water 50 gals. 200 liters 10 minutes

9. Cine Green 8 ozs. 250 grams
Cine Blue 8 ozs. 250 grams
Water 50 gals. 200 liters 10 minutes

10. Cine Blue 8 ozs. 250 grams
Water 50 gals. 200 liters 10 minutes

11. Cine Blue 4 ozs. 125 grams
Water 50 gals. 200 liters 10 minutes

12. Cine Blue 8 ozs. 250 grams
Cine Red 4 ozs. 125 grams
Water 50 gals. 200 liters 10 minutes

Method of Mixing

Dissolve the solid dyes in as small an amount of hot water as
possible, and filter through fine muslin. Pour hot water over any
residue remaining, which should only be slight, in order to ensure
thorough solution of the dye, and dilute the solution in the tank to
the required volume at 65 degrees F.

Nature of Positive Film

Only good snappy positive film may be successfully tinted, since
tinting tends to reduce contrast.

The depth of the tint obtained depends on the following factors:

Nature and Strength of the Dye-bath

Except in special cases such as fire scenes, sunset and moonlight
effects, and the like, it is very undesirable to employ strong tints,
since apart from the displeasing effect and irritation to the eye,
the dyes produce a slight softening of the gelatine film when used at
80 degrees F. in 1% solution.

Should it be necessary to employ concentrated baths in summer,
either cool the dye-bath or use a suitable hardener. This will
be unnecessary if hardener is employed in the fixing bath after
development, but otherwise if formalin (40%) be added to the dye-bath
to the extent of 1 volume to 400 volumes of dye solution, no trouble
will be encountered. During the winter months, when it is advisable
to treat all film after developing and fixing, with glycerine, the
latter may be incorporated with the dye-bath, thereby eliminating
an extra operation. The strength of the glycerine should be 2%, or
two volumes per one hundred volumes of dye solution. In most cases,
however, the addition of glycerine considerably retards the rate of
dyeing, so that in order to obtain the same degree of tinting within
a period of ten minutes, the concentration of the dye-bath should be
increased accordingly.

When delicate tints are employed, the effect is both to remove the
contrasty black and white effect, and to add a touch of warmth to
the black deposit of silver, even in cases where the highlights are
insufficiently stained to be noticeable. The result in many cases is
equal to that obtained by partial toning, for example, tint No. 11
gives the effect of a blue-black tone.

Temperature of Dye-bath

Although temperature has little effect on the rate of dyeing with
the dyes recommended, when used without the addition of acid it is
advisable in all cases to work at 65 to 70 degrees F. in order to
produce uniform results and remove any danger of softening the film.

Time of Dyeing

In order to duplicate any particular tint with a given dye-bath the
film may be dyed either by time or by inspection. Dyeing by time is
reliable if the dye-bath does not contain acid, though if acid is
present, in time the acidity decreases, causing a slowing down of the
rate of dyeing so that it becomes necessary to judge the progress of
dyeing by inspection.

If two or more tints of the same color are required, in order to
reduce the number of individual dye-baths to a minimum, it is better
to vary the time of dyeing rather than to vary the dilution of the
bath, providing the time of dyeing for the lighter tint is not
less than one minute, which time is considered a minimum for the
production of uniform results and for complete control of the dyeing
operations.

The time of dyeing also depends somewhat on the previous handling of
the film. Film which has been fixed in a bath containing ordinary, or
chrome alum, dyes more quickly than that treated with plain hypo and
hardened with formalin.

It is probable therefore, that small traces of alum are left in the
film even after prolonged washing, which serve as a mordant for the
dye.

The film samples herewith shown were fixed in the regular acid hypo
bath, so that if for any reason the tints indicated are not obtained
in the time stated, then either the time of dyeing or the dilution of
the dye-bath should be altered accordingly.

Should the film for any reason be over-dyed, a small portion of the
dye may be removed by washing for 10 to 15 minutes, though the nature
of the dyes will permit only slight mistakes to be rectified in this
manner.

Life of the Dye-baths

This averages about 40,000 feet per 50 gallons of dye-bath. The baths
may be revived at intervals by the addition of more dye, though this
procedure is uncertain and it is generally advisable to mix fresh
solution.

The addition of a trace of acetic acid (1 part in 1000) will revive
an apparently exhausted bath though as stated above, it is only
advisable to do this in the case of baths containing a single dye.

Method of Procedure

Either the “drum” or “rack” method may be employed, and in either
case after dyeing for ten minutes (during which time the drum or rack
should be agitated to ensure even dyeing and prevent accumulation of
air bubbles) the film should be given a thorough rinse in plain water.

Before drying films on racks it is advisable to set the rack at a
slight angle for a few minutes, to enable the surplus water to drain
off more readily through the perforations. If drums are used for
drying it is advisable to remove the surplus water by whirling the
drum previous to drying.

If uniform results are to be obtained, film should never be passed
through the projector before either tinting or toning.

How to Obtain Intermediate Tints

The twelve tints above are given merely as examples; other tints
may be readily obtained by making a trial with a small amount of
solution on a short length of film, taking care to match the tint in
artificial light and not by daylight, since any dye containing Cine
Blue appears redder by artificial light than by daylight.

When matching think of the tint as being made up of one or more of
the colors, red, yellow, and blue. Colors such as orange are made
by mixing yellow and red, violet by mixing red and blue, and green
by mixing yellow and blue. Browns are obtained by mixing all three
colors red, yellow, and blue.

When comparing any two particular tints, it is usual to say that
one is redder, yellower or bluer than the other, and the two may
therefore be matched accordingly.

Choice of Tint

Almost any tint if delicate may be employed with advantage, though
for general use those ranging through pink, rose, orange, yellow,
pale green and pale blue are to be recommended; others are for
special purposes.

It is always desirable to obtain harmony in color, especially when
combining tinting with toning, so that the combination is pleasing to
the normal eye.

For local tinting and hand coloring, the above dyes are likewise
satisfactory.

TROUBLES IN TINTING

Streaks and Uneven Coloring

Cause

a. Grease on the film. Never project film before tinting.

b. Slight bleeding and insufficient squeegeeing when on the drying
rack. Always carefully remove any surface moisture from the film with
a damp chamois, before drying.

Sludge in the Dye-bath

This is due to the precipitation of the dye by small traces of alum
or iron in the water supply. In many localities water is purified by
adding alum, and only the smallest trace need be present to throw
some of the dye out of solution.

Frothing of the Dye-bath

This occurs only when tinting on the drum with Cine Scarlet, Cine
Orange, and Cine Green, but no inconvenience will be caused if the
drum is revolved slowly.

FOOTNOTES:

[1] The patent rights to this method are being secured by us, but it
may be freely used for toning motion picture film manufactured by the
Eastman Kodak Company.

PART II.

TONING

As distinct from tinting, a toned image consists of a color image
embedded within a layer of colorless gelatine, so that while the
highlights are clear, the shadows are colored.

The coloring matter may consist of an inorganic colored compound or
a dye, or of a mixture of both, and by wholly or partially replacing
the black and white silver image by one or more of these substances,
a colored image is produced.

It is, of course, important that the colored compound should be as
transparent as possible so that the full tone will be apparent on
projection. In this respect, while some samples of toned film appear
colored in the hand, they produce a substantially black and white
image on projection, so that when judging any particular tone, it is
absolutely necessary to view the image on the screen.

Of the various inorganic colored compounds, the metallic
ferrocyanides are the most suitable for toning purposes of which:

Iron (ferric) ferrocyanide is blue,
Copper ferrocyanide is red, and
Uranium ferrocyanide is reddish brown.

It is the object in toning to replace the metallic silver composing
the image more or less by one of the above compounds or by a mixture
of these. In this way intermediate tones are obtained.

Toning may be effected either by a single solution process or a two
solution process.

Two Solution Process

This consists of first converting the silver image into silver
ferrocyanide by a suitable bleaching bath, thoroughly washing, and
acting upon the ferrocyanide image with a metallic salt, usually in
presence of an acid, the metallic ferrocyanide being produced by
double decomposition. The reaction, however, is never complete, so
that the image is mixed with undecomposed silver ferrocyanide which
tends to make the image opaque, but at the same time it also adds
“body” to the latter. Providing allowance is made in the original
positive for this intensification, good tones are obtained. (See Tone
G.)

Single Solution Process

Instead of the two separate baths used above, a single solution may
be employed consisting of a metallic ferricyanide dissolved in a
suitable solvent (say, an alkali salt of citric, tartaric, or oxalic
acids) in presence of an acid and certain other salts.

On immersion of the positive film in this solution the silver image
is converted to silver ferrocyanide, while the colored ferrocyanide
is formed simultaneously and combined with it.

In either of the above cases in view of the fact that the metallic
ferrocyanide is deposited in a colloidal condition in presence of the
gelatine of the film, its state of division and the nature of the
tone are usually affected by the presence of certain salts, changes
of temperature, concentration of the baths and other factors which
must be maintained constant in order to obtain uniform results.
With such single baths it is possible to secure tones which are
unobtainable by a two solution process, though as such single
solutions are sensitive to light and rapidly attack foreign metals
which may be present in the shape of faucets, etc., such solutions
are comparatively unstable and require care in their use.

DYE TONING

Owing to the limited number of colored inorganic compounds available
for toning purposes, it is possible to obtain only a limited range of
tones by the above methods.

In view of the possible wide range of colors obtainable by the use
of dyes, it has long been considered that a satisfactory method of
producing a dye image would be the ideal method for toning purposes.

As a result of recent work in our Research Laboratory, it is now
possible to recommend such a method of toning which depends upon the
fact that certain inorganic compounds, including copper ferrocyanide,
have the property of mordanting certain basic dyes, so that when
they are immersed in a solution of the dye the latter attaches itself
to the mordant, which in turn becomes colored.

The most suitable dyes for dye toning are those which do not readily
dye gelatine so that on immersing, say, a sample of copper toned
film in a weak solution of the dye containing a little acid, the
dye becomes mordanted to the image, while the highlights consisting
of clear gelatine remain colorless, the resulting tone being a
combination of the color of the toned film and the dye.

Full particulars are given under tones J, K, L, M and N.

Nature of the Positive to be Toned

Since most toning processes either intensify or reduce the original
image, in order to obtain uniform results, _commence toning with
positive film of the correct density_.

Three standards of positive film have been chosen: Thin, Medium and
Normal. (See chart.) The “Thin” and “Medium” standards are obtained
by giving a slight overexposure and a shorter time of development.

The exact degree of intensification which takes place in any
particular case will soon be learned after a few trials.

Nature of the Developer

Any good Elon-Hydrochinon, Kodelon-Hydrochinon, or straight
Hydrochinon formula will give satisfactory tones, though in the case
of Tone G an Elon-Hydrochinon developer is essential in order that a
rich olive color may be obtained.

For toning, it is necessary that the developed film should be
entirely free from fog, since a thin veil becomes intensified in most
of the toning processes. Fog may be caused by:

(a) Oxidation of the developer, noticeable by the brown coloration
produced after continued use. The remedy is to renew the developer.

(b) Carelessness in compounding the developer. The usual mistake
consists in adding the carbonate to the Elon and Hydrochinon without
previously adding a portion of sulphite to prevent oxidation. It
is not advisable, however, to add the whole of the sulphite to the
Elon and Hydrochinon in the first place, otherwise the Elon may
precipitate. Mixing the developer with water which is too warm will
often cause fog.

(c) The presence of copper, brass, and tin, the fumes from sodium
sulphide, etc., in the developing baths are to be strictly avoided.
A salt of copper if present only to the extent of one part in 10,000
will produce fog on cine positive film.

Fixing

This operation should be complete and, if possible, carried out in
two consecutive baths and followed by thorough washing, otherwise
uneven coloring will result.

In order to eliminate any possibility of uneven toning it is always
advisable to tone immediately after washing and before drying.

Control in Toning

As in the case of tinting, the nature of the tone obtained with the
various solutions depends on the following factors:

a. _The nature and dilution of the toning solutions._ Except in those
cases where it is recommended to revive the bath by adding more
acid, it is not advisable to modify the composition or dilution of
the various solutions, as these have been adjusted to give the best
results.

b. _Temperature of toning._

In most cases a change of temperature from 60 to 70 degrees F. has
merely the effect of changing the time of toning. It is advisable,
however, to maintain the temperature of the various solutions between
65 degrees and 70 degrees F.

c. _Time of toning._

Except in the case of tones F and G when toning proceeds to a limit,
the nature of the tone produced varies with the time of toning,
reaching a limit in from 10 to 15 minutes, so that in a shorter time
intermediate tones are produced. Since most of the toning processes
intensify the original image, if an intermediate tone is required, it
is usually necessary to commence toning with denser film than when
toning is to be carried to the limit. See tones B, C and D.

When producing intermediate tones, it is therefore possible either to
tone in the normal bath for a given time or in a diluted bath for a
longer time. In order to reduce the number of individual toning baths
to a minimum it is recommended to vary the time of toning rather than
to vary the dilution of the bath and to judge the tone by inspection.
Since the strength of the toning bath falls off with use, inspection
is necessary in all cases except Tones F and G.

Before commencing work with any bath, it is advisable to make a test
on a short length of film.

Permanency of Tones

The permanency of the tones produced largely depends on the care
exercised throughout the various operations.

The silver sulphide image may be considered permanent, though in the
other cases, where more or less silver ferrocyanide is present, the
toned image is not absolutely permanent, being somewhat soluble in
hypo and affected by fumes of sulphuretted hydrogen.

In the case of the iron and uranium tones, the colored ferrocyanides
are dissolved by alkali such as sodium carbonate, so that the toned
film should not be washed for too long a time in water which is at
all inclined to be alkaline.

In no case however, if the instructions are carefully followed
will the toned image deteriorate during the active life of the
film. Moreover, so far as can be ascertained, the wear and tear of
film which has been toned by the methods recommended is in no way
impaired, though by virtue of the hardening action of most of the
toning baths on the gelatine it is advisable, especially during the
winter months, to immerse the film for three or four minutes in the
usual 2% glycerine bath after toning.

Should film have to be stored for long periods of time, toning
is inadvisable, nor is it advisable to tone valuable film unless
duplicates are available.

The _life_ of the toning bath has been carefully investigated in
each case, the term “life” being considered as the total length of
film capable of being toned by a given volume of fresh solution when
toning is conducted continuously and without interruption.

In all cases it is false economy to exhaust a toning bath to the
limit and thus obtain inferior tones, since the cost of the chemicals
employed is insignificant compared with the value of the film being
treated.

Since the figures given represent the capacity of the bath for
toning under the best conditions, they only apply providing the baths
are kept covered as far as possible when not in use, to exclude
light, and providing no foreign metallic surface, however small, is
allowed to come into contact with the solution.

As mentioned above, single solution baths are not intended for
occasional use. In such cases two-solution methods should as far as
possible be employed, although it has only been possible to recommend
the latter for the production of sulphide and blue-green tones.

Stability of the Solutions

All toning solutions containing potassium ferricyanide are sensitive
to light, the ferricyanide being reduced to ferrocyanide. Therefore
when not in use the tanks should be carefully covered so as to screen
the solutions from sunlight.

It is also very important that no metallic surface however small
should come in contact with the solutions; any metal pegs on the
racks or pins used to hold the film together will gather the tone in
preference to the film, causing the formation of sludge. Plain wooden
racks with or without wooden pegs should be used, and metal faucets
replaced by wooden plugs.

If any considerable amount of sludge forms in the tank at any time,
it is due either to incorrect mixing, the action of light, or to the
presence of foreign metallic substances.

TONE A

_Tone A_ Red (Copper)

_Positive Employed_—Normal

After immersion of the well washed film in water for one minute,
bathe in the following:

Avoirdupois Metric

Copper sulphate 1 lb. 11 ozs. 800 grams
Ammonium citrate (neutral) 5 lbs. 3 ozs. 2500 ”
Potassium ferricyanide 1 lb. 11 ozs. 800 ”
Ammonium carbonate 13 ozs. 400 ”
Water to 50 gals. 200 liters

Dissolve each ingredient separately in as little water as possible,
mix the filtered solutions so obtained in the order given, and dilute
to the required volume. The solution obtained should be light green
in color and perfectly clear. The ammonium carbonate should be almost
transparent and free from white powder, and should be dissolved in
cold water, while the ammonium citrate employed should be neutral.
Most samples contain acid, which acid would neutralize the ammonium
carbonate and affect the resulting tone. The free acid is usually
citric acid, and should be neutralized with a solution of ammonia
using litmus as indicator.

_Temperature of Toning_—To obtain the best results the temperature of
the bath should be from 65 degrees to 70 degrees F.

_Time of Toning_—Five to ten minutes.

_Time of Washing_—10 minutes.

_Life of Bath_—With use the bath precipitates a brown sludge of
copper ferrocyanide, and in consequence becomes weaker by virtue of
the loss of copper, though 50 gallons of the solution will tone about
10,000 feet of film.

It is necessary to keep the film entirely submerged in the tank,
or constantly in motion when on the drum, otherwise if the film is
frequently examined, especially during the first few minutes of
toning, streaks are liable to occur.

TONE B

_Tone B_ Red (Uranium)

_Positive Employed_—Thin.

Immerse the well washed film in the following:

Avoirdupois Metric

Uranium Nitrate (Neutral) 16½ ozs. 500 grams
Potassium Oxalate (Neutral) 16½ ozs. 500 grams
Potassium Ferricyanide 6½ ozs. 200 grams
Ammonium Alum 2½ lbs. 1200 grams
Hydrochloric Acid 10% 1 quart 1000 cc.
Water to 50 gals. 200 liters

Mix in the order given. The solution obtained should be perfectly
clear and pale yellow in color.

In view of the fact that the nature of the tone is influenced largely
by the acid content, it is very important that the uranium nitrate
should contain no free acid, and this may be assured by neutralizing
a solution with dilute ammonia until a slight permanent precipitate
is obtained.

It is convenient to keep stock solutions of the above (say, 10%
solutions) from which a new bath may be expeditiously compounded. A
10% hydrochloric acid solution is one containing 10 parts by volume
of the concentrated acid per 100 volumes of the final solution.

_Temperature of Toning_—65 degrees to 70 degrees F.

_Time of Toning_—Ten minutes.

Since this and the following single solution methods of toning
produce a marked intensification of the silver image—which
intensification increases with the time of toning—it follows that the
nature of the tone changes with time also.

The composition of the bath has been so adjusted that the maximum
effect is produced in about 10 minutes, the tone passing through a
series of changes from brown to red during this time.

It is therefore possible to obtain intermediate tones by withdrawing
the film from the bath at shorter intervals, though in such cases
the contrast of the original black and white film should be adjusted
accordingly, since with slight toning very little intensification
takes place. (See tones C and D.)

_Time of Washing_—Ten to fifteen minutes.

The highlights will become clear in the above time, though a thin
yellowish brown veil may remain in the clear gelatine as a result of
the intensification of minute traces of fog, but this has no effect
on projection. If the bath is working correctly the yellowish veil is
only just perceptible, but if appreciably visible, then either the
film was fogged during development, or the bath was not compounded
correctly. Washing should not be carried out for too long a period,
especially with water inclined to be alkaline, because the toned
image is soluble in alkali.

_Life of Bath_

Fifty gallons of solution will tone about 5000 feet of film without
any appreciable change in the tone, after which the rich tone tends
to flatness as a result of a deficiency of acid in the bath. At this
point the bath may be revived by the further addition of acid to the
extent of the original amount, when a further 5000 feet may be toned.
At this stage the richness of tone falls off rapidly and the bath
should be thrown away.

Used intermittently over a period of several days the life of the
bath is approximately the same.

With continued use a slight brownish flocculent precipitate may
form in the bath, but this should only be slight, otherwise it is
caused by incorrect mixing, the action of light, or by contact with a
metallic surface.

TONE C

_Tone C_—Red Brown (Uranium)

_Positive Employed_—Medium

The toning formula employed and the instructions to be followed are
the same as for Tone B, the time of toning being about 5 minutes at
65 degrees to 70 degrees F.

TONE D

_Tone D_—Brown (Uranium)

_Positive Employed_—Normal

The toning formula employed and the instructions to be followed are
the same as for Tone B, the time of toning being about 3 minutes at
65 degrees to 70 degrees F.

TONE E

_Tone E_—Sepia (Uranium and Iron)

This particular tone is obtained by suitable mixture of red and blue
toning solutions. By varying the proportions of these baths, tones
varying from red to sepia may be obtained.

The following is only one of the many tones produced by this method.
Increase in the proportion of the iron bath makes the tone colder,
and vice versa.

_Positive Employed_—Medium

Immerse the well washed film in

Solution for tone B (red brown) 5 vols.
Solution for tone H (blue) 1 vol.

_Time of Toning_ 3 to 4 minutes at 65 degrees to 70 degrees F.

The instructions regarding method of procedure, life of bath, etc.,
are exactly the same as for tone B.

TONE F

_Tone F_ (Sulphide)

_Positive Employed_

With a thin positive a warm brown tone is obtained, while with denser
film the effect is that of a blue-black tone.

Avoirdupois Metric

_A._ Potassium Ferricyanide 8 lbs. 5 ozs. 4000 grams
Potassium Bromide 2 lbs. 2 ozs. 1000 grams
Water to 50 gals. 200 liters

_B._ Sodium Sulphide (crystal) 2 lbs. 2 ozs. 1000 grams
Water to 50 gals. 200 liters

A trace of iron in the sodium sulphide will do no harm providing the
solution is boiled and the precipitated iron sulphide allowed to
settle before use. The well washed positive is thoroughly bleached in
A, washed for 5 minutes, and immersed in solution B until the film is
thoroughly toned.

_Temperature of Toning_—65 degrees to 70 degrees F.

_Time of Toning_—Four to five minutes.

_Time of Washing_—Ten to fifteen minutes.

_Life of Baths_

The toning baths A and B are comparatively stable and will keep until
exhausted.

TONE G

_Tone G_—Olive Green (Iron)

_Positive Employed_—Thin to medium.

The best tones are only obtainable on film developed in an
Elon-Hydrochinon developer. Thoroughly bleach the well washed film in:

Avoirdupois Metric

_A._ Potassium Ferricyanide 20 lbs. 12 ozs. 10,000 grams
Ammonia (concentrated
.89) ½ gal. 2 liters
Water to 50 gals. 200 liters

_Time of Bleaching_—Two to five minutes.

After washing for 10 to 15 minutes, tone in the following at 65
degrees to 70 degrees F.:

Avoirdupois Metric

_B._ Ferric Alum (Ferric
Ammonium Sulphate) 4 lbs. 2 ozs. 2000 grams
Potassium Bromide 2 lbs. 2 ozs. 1000 grams
Hydrochloric Acid
(concentrated) 13 ozs. 400 cc.
Water to 50 gals. 200 liters

_Time of Toning_

Toning should be complete in from 3 to 5 minutes.

_Time of Washing_—Ten to fifteen minutes.

If the highlights are stained blue, or if the image will not
completely tone in the shadows, this is due to _insufficient washing
after bleaching_. When bleaching, it is important to examine the film
as little as possible, otherwise streaks are liable to be produced
due to the action of the air at those parts where the solution
drains off the film. It is also important to tone immediately after
bleaching and washing.

_Life of Baths_

Bleach A.

Providing the solution is screened from the light and kept covered
to prevent the undue escape of ammonia, the bath keeps fairly well,
but if it shows any signs of weakening, it should be revived by the
addition of a further quantity of ammonia equal in amount to that
originally used. If so revived at intervals, 50 gallons will bleach
40,000 feet of film before exhaustion.

Solution B.

Fifty gallons of solution B will tone 30,000 feet of film without
further addition of acid, when it should be thrown away.

TONE H

_Tone H_ Blue (Iron)

_Positive Employed_ Thin or Medium, according to result desired.

Tone in the following:

Avoirdupois Metric

Potassium Bichromate 75 grains 5 grams
Ferric Alum (Ferric
ammonium sulphate) 8 ozs. 85 grs. 250 grams
Oxalic Acid 1 lb. 4 ozs. 600 grams
Potassium Ferricyanide 6½ ozs. 200 grams
Ammonium Alum 2 lbs. 2 ozs. 1000 grams
Hydrochloric Acid 10% 6½ ozs. 200 cc.
Water to 50 gals. 200 liters

The method of compounding this bath is very important. Each of the
solid chemicals should be dissolved separately in a small quantity
of warm water, the solutions allowed to cool, filtered into the tank
strictly in the order given, and the whole diluted to the required
volume. If these instructions are followed, the bath will be a pale
yellow color, perfectly clear, and will remain so for a considerable
period.

_Time of Toning_—Five to ten minutes at 70 degrees F.

_Time of Washing_

Wash for ten to fifteen minutes until the highlights are clear. A
very slight permanent yellow coloration of the clear gelatine will
usually occur, but should be only just perceptible, when it will have
no effect on projection. If the highlights are stained blue, then
either the film was fogged during development or the bath was not
compounded correctly. Washing should not be carried out for too long
a period, especially with water inclined to be alkaline, because the
toned image is soluble in alkali.

_Life of Bath_

If the acid is renewed to the extent of the original amount after
toning each 5000 feet, the bath is capable of toning 15,000 feet per
50 gallons of solution.

If even after revival, the tone remains flat, the bath is exhausted
and should be thrown away.

After continued use, a slight bluish sludge will collect in the
bath, but this is not harmful. Should this form, however, to any
appreciable extent, it is due either to incorrect mixing, the action
of light, or to contact with metallic surfaces.

TONE I

_Tone I_—Pale Blue (Iron)

The instructions are as for Tone H with the following modifications:

_Positive Employed_—Normal.

_Time of Toning_—Two to four minutes according to depth of tone
desired.

NEW TONES

TONE J

_Tone J_—Red (Dye Tone)

By first toning in Tone A, washing, and then immersing the copper
toned film in an acid solution of a basic dye, the dye is mordanted
to the toned image, thus modifying the color.

_Nature of Positive_—Medium

Tone for five to ten minutes in solution as for Tone A, and after
washing for ten minutes immerse in the following dye-bath.

Avoirdupois Metric

Safranine A (National
Aniline and Chemical
Co., Inc.) 7 ozs. 200 grams
Acetic Acid (Glacial) 32 ozs. 1000 cc.
Water to 50 gals. 200 liters

_Time of Toning_

Five to ten minutes, according to depth desired.

_Temperature of Toning_—65 degrees to 70 degrees F.

_Time of Washing_

Usually only a slight rinse in water is necessary. If the highlights
are stained, the film should be washed for five or ten minutes or
until clear. Stained highlights are caused either by insufficient
washing after toning, too strong a dye-bath, or an incorrect amount
of acid in the dye-bath.

TONE K

_Tone K_—Orange (Dye Tone)

The instructions are exactly as for Tone J, substituting the
following dye-bath.

Avoirdupois Metric

Chrysoidin 3R (National
Aniline and Chemical
Co., Inc.)
or Chrysoidin Y (Extra) 2 ozs. 320 grs. 80 grams
Acetic Acid (Glacial) 32 ozs. 1000 cc.
Water to 50 gals. 200 liters

TONE L

_Tone L_—Violet (Dye Tone)

The instructions are exactly as for Tone J, substituting the
following dye-bath:

Avoirdupois Metric

Methyl Violet (National
Aniline and Chemical
Co., Inc.) 2 ozs. 320 grs. 80 grams
Acetic Acid (Glacial) 32 ozs. 1000 cc.
Water to 50 gals. 200 liters

Intermediate Dye Tones

The depth of the dye tone is determined by the time of immersion
both in the copper toning bath and in the dye-bath. Pale tones may
therefore be obtained either by giving a short bath in Tone A and
fully dyeing, or by toning for a longer time and giving a short
immersion in the dye-bath.

By mixing the dye-baths J, K, and L in varying proportions
intermediate colors may be obtained just as in tinting.

TONE M

_Tone M_—Pale Red (Dye Tone)

_Positive Employed_—Normal

Tone for one to two minutes in Tone A, wash for ten minutes and then
immerse in the following dye-bath.

Dye solution for Tone J, one volume.
Dye solution for Tone K, one volume.

When the desired tone is obtained rinse until the highlights are
clear.

Compound Tones

TONE N

_Tone N_—Copper-Iron-Dye Tone.

By first partially toning the black and white film (Medium) in Tone
A for three to four minutes at 65 degrees to 70 degrees F., so that
the half-tones are completely toned but the shadows only partially,
washing for ten minutes and then completing the toning process in the
blue toning bath H, the residual silver in the shadows is toned blue.
In this way a double tone is obtained, the shadows appearing dark
blue and the half-tones reddish brown.

By immersing the film toned in this manner in the Chrysoidin dye-bath
as given under Tone K, the dye is mordanted to the half-tones which
contain copper ferrocyanide, producing the effect indicated.

Combined Tinting and Toning

In many cases pleasing effects may be obtained by tinting film which
has already been toned, the result being that the clear portions
or highlights assume the color of the dye, while the shadows and
half-tones project a tint intermediate between that of the dye and
the toned deposit.

Considerable judgment is necessary, however, in choosing suitable
tints to blend with any given tone.

The most successful combination of toning with tinting is in the
production of sunset and moonlight effects over water, by first
toning blue and then tinting orange, red or yellow.

The following combinations will cover most cases required:

Tones A, B, C, D, E, F, J, K, L. Tints Nos. 2, 5, 6.

Tones G, H, I. Tint almost any delicate shade.

It is considered unnecessary to illustrate every combination of tone
and tint above, so that only typical examples are given. It must be
noted that toned film (except tones A and F) absorbs the dye more
quickly than untoned film, so in order to duplicate appended samples,
the dye-baths should be diluted accordingly.

Very pleasing effects may also be obtained by locally tinting toned
film, the color being applied either by hand with a brush, or by
stencilling.

Equipment

The equipment necessary for systematic tinting and toning is
essentially the same as that required for development, consisting of
the usual tanks and racks or small drums, only it is advisable that
they should be used for this purpose exclusively and, if possible,
occupy a separate room to exclude any possibility of contaminating
the developing solutions by the copper or sulphiding bath, which
would cause development fog immediately.

The “drum” system, on account of the expense involved in apparatus
and the larger space required for manipulation, is not to be
recommended for tinting and toning operations, though for operation
on a small scale, a small wooden drum revolving in a shallow wooden
tank is most efficient and economical.

When the tank and rack system is employed, the tanks should be of
slate or other resistive material, and have an outlet at the bottom
in the form of a hard-rubber stopcock or a plain wooden plug. The
racks or drums may be of wood, but if metal pegs are employed on
the racks they should be coated with acid-resisting paint such as
asphalt, since the presence of any metallic surface in the toning
baths will cause contamination and effect a precipitation of sludge.
The frames should not be interchanged but kept separate either for
tinting or toning to prevent contamination of one bath with racks
previously employed in another. This also applies to the small drum
system. For instance, a pink tint would be ruined by using a rack
which had previously been immersed in a deep blue dye-bath, unless
that particular rack had been thoroughly washed. In the case of
delicate tinting, however, no harm is done providing the racks have
been previously coated with the following waterproof varnish:

Avoirdupois Metric

Hard paraffin 3½ lbs. 1600 grams
Carbon tetrachloride 10 gals. 40 liters

Before treatment it is preferable to immerse the racks which have
been previously used for developing, in a 1% solution of hydrochloric
acid for two or three minutes, wash for fifteen minutes and
thoroughly dry. The well-dried racks are then dipped in the above
solution and the excess liquid drained off, when the varnish dries
almost immediately. The varnishing should be repeated at intervals.

Mixing Solutions

Developers, toning solutions and dyes should be mixed in crocks of
glazed earthenware or enameled iron, using warm water where necessary
and ensuring thorough solution by stirring with a wooden paddle,
which should be thoroughly washed after each operation. Having
thus dissolved the chemicals in as small a quantity of warm water
as possible, filter through fine muslin and make up the bath with
cold water, so that the final solution will be at approximately the
correct temperature.

The chemicals employed should be pure (for the samples, “EKCo.”
tested chemicals were used), and in cases where a good water supply
is not available, only distilled water should be used.

Troubles in Toning

Most difficulties met with in toning may be traced to one or more of
the following causes:

_Uneven Toning_

This may be due to:

a. Grease on the film. Never project film before tinting or toning.

b. Drying spots on untoned film. If possible, always tint or tone
film immediately after washing and before drying.

c. Examination of the film too frequently during toning, causes an
oxidation of the toning solution in places where the solution fails
to drain from the film.

d. Insufficient or uneven washing of the film after bleaching and
before toning (Tones F and G).

_White Spots_

White spots are produced by particles of hypo or carbonate dust or
splashes of a solution of these, settling on the toned film. The
toned image consists of silver together with more or less silver
ferrocyanide and the ferrocyanides of uranium, iron and copper as the
case may be. Silver ferrocyanide is soluble in hypo while uranium and
iron ferrocyanides are soluble in a solution of sodium carbonate,
strong ammonia, etc., so that the white spots indicate those parts
where the toned image has been dissolved away.

Irregular white spots may also be formed if the film is imperfectly
squeegeed after washing and before drying, especially if the wash
water is slightly alkaline. When a spot of water on the toned film
evaporates, the small amount of alkali present in the water becomes
more concentrated and finally dissolves away more or less of the
tone, leaving a white spot on the film.

White spots due to these causes may be prevented by immersing the
film for a few seconds in a .5% solution of glacial acetic acid after
toning and before placing on the drying rack.

_Stained Highlights_

Are caused by:

a. Traces of fog on the film before toning.

b. An improperly compounded toning bath. All solutions when new
should be perfectly clear.

c. Premature exhaustion of the bath. This is due either to the action
of light or to the presence of some metal in the tank in the shape of
screw heads, faucets, pins, etc., which gather the tone and cause the
formation of sludge.

It is important to keep all solutions containing potassium
ferricyanide exposed as little as possible to daylight, to use only
wooden racks with wooden pegs, and to cover all metal parts very
carefully with acid resisting paint.

d. In dye-toning, stained highlights are due either to insufficient
washing after toning with copper, too strong a dye-bath, or an
incorrect amount of acid in the dye-bath.

Tints

[Illustration: 1]

[Illustration: 2]

[Illustration: 3]

[Illustration: 4]

[Illustration: 5]

[Illustration: 6]

[Illustration: 7]

[Illustration: 8]

[Illustration: 9]

[Illustration: 10]

[Illustration: 11]

[Illustration: 12]

[Illustration: tint]

Tones

[Illustration: Thin]

[Illustration: Medium]

[Illustration: Normal]

[Illustration: A]

[Illustration: B]

[Illustration: C]

[Illustration: D]

[Illustration: E]

[Illustration: F]

[Illustration: G]

[Illustration: H]

[Illustration: I]

[Illustration: tones]

Tinted and Toned

[Illustration: J]

[Illustration: K]

[Illustration: L]

[Illustration: M]

[Illustration: N]

[Illustration: Tone J Tint 6]

[Illustration: Tone C Tint 1]

[Illustration: Tone C Tint 4]

[Illustration: Tone C Tint 6]

[Illustration: Tone H Tint 2]

[Illustration: Tone H Tint 6]

[Illustration: Tone H Tint 8]

[Illustration: tinted and toned]

Transcriber’s Notes

pg 29 Changed: the tanks shoud be of slate
to: the tanks should be of slate

*** End of this LibraryBlog Digital Book "Tinting and toning of Eastman positive motion picture film : Second edition—revised" ***

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