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.