BROMOIL TRANSFER
BY EUGEN GUTTMANN
The idea of transferring a bromoil print to an ordinary, uncoated paper
was first introduced by the English and later further worked out by
the French. The Germans turned to this new process comparatively late,
but obtained fine results. Yet the practice of this beautiful form of
artistic photography was limited to a small circle of adherents, and
even to-day, when bromoil printing, thanks to the instruction of some
excellent textbooks, has become known to almost all artistic workers, one
cannot state that it enjoys wide popularity. This may well come from the
fact that not everyone has the absolutely necessary printing machine, and
that the substitutes for this machine, such as burnishers and washing
mangles, cannot bring out all that lies in the process. In addition, when
the process was first introduced, the transfers were never strong enough,
and were mostly muddy and flat. This happened because, in the first years
of the process, strong and vigorous shadows were not produced on the
paper. The English and French improved this by pigmenting the shadows of
the bromoil print much more strongly than was needed for this process.
They stated that the chromated film took the ink very readily in the
shadows, but parted with it again very unwillingly. Thence they concluded
that, in order to be able to transfer much ink to the paper, a surplus
of ink must be imparted to the shadows; they thus corrected the tone
values by deepening the shadows, and contended that they produced their
beautiful transfers in this way. I have never seen an English transfer,
but plenty of the French, which were said to have been prepared in this
way. From my own experiments extending over a long period, I doubt
whether the depth in the shadows could be attained in this way, and can
only assume that very important particulars have not been made known in
the excellent publications on this process. A simple reasoning, without
any trial, also leads to the same conclusion. If, for instance, I overink
the shadows by imparting to them more ink than the tone values require,
then I smother all the details in them and in the transfer I shall obtain
a black, absolutely detailless patch. The English and French contend,
however, that all details, which are made invisible by overinking the
bromoil print, become visible again in the transfer. They thus explain
the matter approximately as if we were dealing with a carbon print,
in which the whole film is “reversed” during the development. This is
absurd. A _moderate_ overinking will obviously give better shadows, but
this limitation is of no advantage.
For an important advance in the direction of the production of vigorous
shadows in the transfer we are indebted to the work of Hanns Benndorf,
which was described in an article, “The Technique of the Bromoil Transfer
Process” (_Phot. Rundschau_, 1914, Heft 9, 10). He used the method of
printing in superposition common to all gum printers, since he first
pigmented the original print in a normal manner but with weaker shadows,
printed it and then inked up a second time, treating this time merely
the shadow parts which were to be strengthened, and then printed it on
the first transfer. The results were actually very good. But the process
still required considerable dexterity; its chief difficulties appear to
me to lie in the fact that in the second pigmenting it is uncommonly
difficult to so bring out the shadows that they do not appear too deep
in the final print, and the middle tones and high lights are thus out of
tone. The process is very suitable for bringing out individual parts of
the shadows.
On the other hand a considerable advance in the development of the
process was made by Dr. Emil Mayer, and this consisted of giving to the
bromide print by exposure and development a particular character only
suitable for this purpose. Fuller details of this are given under the
heading “Combination Transfer with one Print Plate,” page 125.
In most publications on bromoil transfer, directions are finally given to
pass the finished bromoil print quickly _once_ through the machine with
a _heavy_ pressure of the rolls, and at the most _twice_. This advice
has received my special attention, because I found that in this way good
as well as bad transfers could be obtained; but I decidedly could not
count on _always_ obtaining equally good results. I noticed that things
went well when I had a pressure on the rolls which was suitable for
the bromoil print and the structure of the paper. Getting this correct
pressure was pure luck. If the pressure was too great, then I indeed got
all the ink on the paper, but the shadows were wanting in detail and
flat; if on the other hand it was too weak, the shadows remained much too
grey.
Hence I came to the idea of so adjusting the rolls that I printed at
first with only a light pressure. I then had as a result a transfer which
was absolutely white in the highest lights, yet showed all the gradations
of the bromoil print in the high lights as well as in the finest and fine
half-tones. The shadows, on the other hand, were grey and not filled up,
for much of their ink still remained on the bromoil print. Then I again
inked the same bromoil print and printed again as before, but did not
take the paper from the machine, observing the transfer by carefully
lifting the bromoil print. It was exactly as described above. Now I
allowed the paper (the lower part of which was still held by the rollers,
further details of which will be found in the section “Printing”) to
again come into contact with the bromoil print, screwed down the central
spindle to increase the pressure, and passed the pack again through the
machine. The result was highly satisfactory. The highest and the high
lights, as well as the half-tones, remained as they appeared at the first
pull, but the shadows were fully filled up and completely transferred
from the bromoil print to the paper.
Thus I had discovered _the principle of printing with increasing pressure
of the rolls_. Further experiments led me to improve the method, and the
following instructions give all necessary explanations and directions.
I must remark that from the start I used a machine the arrangement of
which permitted me to see the print during the printing, and with which
the pressure on the rollers could be regulated at will.
The transfer is not only a step toward the greater development of
the bromoil print, it is so beautiful in its results that no other
photographic process, with the exception of gum printing, at all
approaches it. By the transfer process, photography has made its first
entry into the ranks of the graphic arts. No positive process, other
than bromoil transfer and gum printing, has overcome the oft-bewailed
shortcoming of photography, that there is no sun in the picture, as
well as these two processes. _It is even possible in them to use as the
highest light the pure white of the paper._ In this respect transfer
still has the advantage of offering a more rapid if not an easier
technique.
Certainly the ordinary bromoil print also gives excellent results. Its
whites are, however, formed by the photographic film, and this is its
only disadvantage. There is, however, always a difference of beauty
between a bromoil print and its transfer, the appreciation of which is
purely subjective. We can accept it as certain that feeling in a picture
printed in bromoil is attainable by simpler means than in the more
difficult transfer. The photographic artist will decide for the one or
the other according to the results desired.
THE BROMOIL PRINT.—_For every transfer there must be a bromoil print,
complete in every part._ That is an indispensable requirement for those
who desire to practise transfer.
That a perfect bromoil print can only be prepared from a perfect bromide
print is generally known. It is not my province to describe both
processes fully, for that was long since done by various writers in
excellent works. But it is my duty to give some hints as to the way in
which the bromoil print should be prepared in order to obtain the best
possible results by my new printing technique, which will later be fully
described.
The transfer printer must always keep in view the fact that he must
prepare the way for his final _artistic results_ in all previous phases
of the technical preparation of his print. He will, for this reason,
in a careful and well planned working up of the negative, bring out
the characteristics and feeling of his ideal result by toning down or
suppression of such parts of the picture as may be necessary, a task
which has nothing in common with the process generally called retouching.
He will also make the bromide print, whether by contact or enlarging,
with greater deliberation and care than is used in most cases. Too much
reliance in this respect is often placed on the omnipotent technique of
bromoil, which allows us to carry out the most far-reaching alterations
on the print. This can certainly be done; but perhaps this way is even
more difficult than taking every necessary precaution right from the
start and producing it correctly—in one word: creating it.
Far too little use, for example, is made in enlarging of bolting
cloth, chiffon, or some such open-meshed fabric which, according to
requirements, may be used with wide or narrow mesh, or even doubled,
two pieces in contact [preferably with the threads at an angle of
45°.—Trans.]. Used with discretion, this gives valuable assistance in
producing an artistic softening of contours and contrasts. The same
purpose is attained in perhaps even greater perfection, by using the
procedure recommended by L. Vernouille of Vienna. In this method of
enlarging _two sheets of tissue paper_, of the size of the enlargement,
are laid upon the film side of the bromide paper, and the exposure
is made through these two sheets. It is important that the time of
exposure be exactly determined; this is about double that of the usual
enlargement. The tissue paper must be perfectly white and free from
imperfections, black specks and folds, etc.
Besides these tricks a slight want of sharpness may be used to give the
desired effect, or also the interposition of ruled screens between the
film and the negative.
If it is desired that the bromoil transfer shall show a canvas effect
similar to that of oil paintings, the simplest procedure is as follows. A
piece of cloth is cut from a material which has the necessary structure,
_slightly_ larger than the size of the print, and laid flat on a stiff
support such as pressboard. Then a new piece of carbon paper, such as is
used in typewriting, as thin and free from faults as possible, is cut to
the same size, immersed in water, allowed to drain, and placed smoothly
on the material; a second sheet of pressboard is then placed on top and
the whole subjected to a strong pressure, say between the rollers of a
burnishing machine or washing mangle; if one has not these, then in a
copying press. The carbon paper shows when dry the perfect structure of
the material. If this structure paper is now placed between the paper
and the negative, or in enlarging in contact with the paper, the bromide
print shows this structure together with a very plastic rounded image,
and a longer exposure is not necessary. I consider this procedure better
than the use of the commercial structure screens, since one is free
in the choice of the material from fine lawn to the coarsest canvas,
while among the commercial articles there is seldom one which is quite
satisfactory, and of course no such variety.
The final size of the picture must be drawn on the bromide print in
pencil before the bleaching, for the positions of the edges cannot be
determined on the bleached-out print, especially when the bleaching is
complete. After the bleaching and drying are finished, the pencil marks
should be cut through with a sharp knife on a glass plate, and the print
is thus given the desired size. From this point on, one should be most
careful not to touch the print with the fingers, except on the back,
which can be easily done with a little care, by always lifting up the
edge with a knife.
It is immaterial what bromide paper is used. It may have any surface,
be thick or thin, though thick paper is to be preferred. For prints and
transfers which should show the greatest possible fineness and modeling,
it is better to choose a smooth bromide paper.
The prepared print is swollen and pigmented as in making an ordinary
bromoil print. _It is not necessary, when planning to make a transfer, to
produce a higher relief by a warm water or ammonia bath_, which requires
the use of softer inks and limits artistic freedom in working up. One’s
whole attention must be focused on a _single point_: the shadows must be
_clean_, the lights _pure white_. If this condition be neglected a good
transfer cannot be expected. Deviations from this fundamental requirement
are only permissible for those who have absolutely mastered the printing
technique, and who, therefore, can foresee the results with certainty.
One must take into account the fact that the transfer process has a very
marked tendency to lower the tones. The high lights and fine half-tones
always appear somewhat darker in the transfer than in the bromoil print,
while the shadows, with _correct printing_, remain the same. It is,
therefore, absolutely necessary to lighten up the high lights and the
fine half-tones just as much as they lose in brilliancy in the transfer.
Obviously no description is of any value on this point; a few experiments
made for this purpose will quickly put one on the right track.
The fact that the bromoil print is _trimmed_ before being placed on the
pad has caused some nervous souls to be afraid that water may thus come
from the support through the brush on to the film, but this is not likely
to occur. The pad should be arranged by first laying on the glass plate
a thoroughly wet copying sheet; on top of this a second sheet is laid,
equally wet and with no air-bubbles between. The water is completely
dried off the surface of the second sheet with the aid of a sheet of
lintless blotting paper, and then one can work all day long even in
summer in the greatest heat without changing the support; there will
always be enough moisture to produce adhesion between the sheet and the
support, but one will never carry a drop of water on to the print with
the brush.
THE CHOICE OF THE PAPER.—The pigmented gelatine film gives up its ink
when it is brought into contact with paper under pressure; from which
it seems that theoretically paper of any quality may be used for the
transfer. In practice the matter is not quite so simple, for every paper
surface possesses an individual character which definitely influences the
ink transfer and the final result.
Papers may be roughly classified as rough, medium and smooth, obviously
with many intermediate grades, each of which may be divided into sized,
half-sized and unsized sorts. Whether a rough, medium or smooth structure
is to be chosen, must be decided from a purely artistic point of view,
and in this decision the character of the subject and the effect desired
are of equal importance. It is different, however, as regards _sizing_.
The quality of the picture frequently depends on a correct decision on
this point. This is at once clear when we consider that unsized paper
is much more porous than half-sized or fully-sized paper, and thus can
remove the ink much faster and more completely from the bromoil print.
If, for example, a bromoil is transferred with a certain roll pressure
on copper-plate paper, that is, on a very absorbent porous paper, the
ink will be quickly transferred to it, whereas a sized paper, under the
same conditions, that is, with the same pressure on the rolls, will take
up only a small part of the ink. A comparison of the two transfers would
then show that the shadows on the copper-plate paper are blocked up and
have lost many details, while those on the sized paper appear much too
light, which is readily understood, as the porous paper has taken up all
the ink, the sized paper merely a portion of it.
How far these properties of papers can be equalized or used will be dealt
with in the section on “Printing.”
In choosing the paper destined for the transfer, therefore, attention
not only has to be paid to the structure, which must serve the artistic
purpose, but one must be certain of the amount of sizing; this latter is
necessary so that one may correctly carry out the actual printing process.
As a basic principle the worker should use only _pure rag paper_ and
avoid all paper containing _wood pulp_. Although theoretically it
cannot be disputed that any paper is suitable for transfer, it is also
practically accepted and undoubtedly correct that _beautiful prints_ can
only be prepared on _good papers_, and the artistic photographer should
not be induced by any consideration to use other than the best materials.
All the commercial drawing and water-color papers of all tints and
structure, made by reliable firms, can be recommended. Extraordinarily
fine results are obtained on copper-plate printing paper, which may be
obtained in white and yellowish tints. Equally as good, and specially
suitable for certain effects, are the Japanese and Chinese papers.
The stock of paper should be kept in a dry place and free from dust.
Printing should only be effected on _dry_ paper. Damp paper is used when
it is _very coarse-grained_ and rough, as then the ink is more easily
taken in the depressions. Such sheets are best dampened by immersing them
for some minutes in water, allowing to drain and passing them through the
machine between two sheets of calendered lintless blotting paper with
strong pressure; they are then immediately ready for printing.
If one has to deal with very absorbent papers, with which, especially in
the pure whites, there is always danger that in spite of careful printing
the gelatine film may adhere to the surface of the paper and thus spoil
both bromoil print and transfer paper, the paper should be given a slight
sizing. The preparations to be used for this should be those used by the
gum printer: gelatine hardened with alum, chrome alum or formaldehyde.
But these solutions must be applied warm and then the original brightness
of the paper suffers. It is, therefore, more advantageous to use the
_cold_ preliminary coating recommended by von Hübl to prevent the
sinking-in of the platinum-iron solution for platinotype; 2 g (60 gr.)
of rice or wheat starch or arrowroot should be rubbed up with a little
water and added with constant stirring to 100 ccm (3 oz.) of boiling
water. When quite cold the solution should be applied evenly to the paper
with a swab. The application must result in a slight matt gloss on the
paper without any damp places anywhere. When dry it is ready for use. The
longer the paper is kept after this preliminary preparation, the better
it is.
The beginner will be well advised always to use one and the same quality
of paper until he has succeeded in attaining full command of the
printing technique; I have already pointed out that papers of different
surfaces take the ink from the bromoils with different degrees of ease
or difficulty. Similar differences also occur with increase of pressure.
When the operator has once become perfectly familiar with the necessary
adjustments of pressure with _one sort_ of paper, he will be able without
difficulty to estimate the degree of pressure for other papers. At the
start it is advisable to use a good, half-sized moderately rough drawing
or water-color paper.
It may be remarked that transfers may be made on silk or other textile
fabrics as well as on paper. If permanent results are desired, care must
be taken that pure fabrics are chosen, that is, such as are not filled,
as is usually the case with silk. As the fillers are usually metallic
salts, they may easily have a destructive chemical effect on the inks.
THE MACHINE.—In order to obtain a good transfer, a machine is required
which must satisfy to the fullest extent two requirements: the pressure
on the rolls must be capable of being regulated at will before and during
the printing, and one must be in a position to examine the condition of
the print at any time, without danger that the bromoil print and the
transfer paper will shift. By pressure on the rolls is meant the distance
between the two cylinder surfaces.
[Illustration: FIG. 1]
The autographic metal hand press, model A, as supplied by the firm
of Hugo Carmine, Vienna VII, at comparatively reasonable prices with
different lengths of rolls, is almost an ideal machine for our purpose.
It is shown in Fig. 1 and consists, as will be seen, of a massive metal
stand, which may easily be screwed to any table. Through the center goes
the lower roll or printing cylinder, which is prepared of an elastic
material, and this stands at the same height as the two tables seen on
both sides. Above this lower, immovable roll, there is the upper one,
which can be set higher or lower as required by the central spindle, in
the center of which is the wheel. The central spindle is so arranged
that the upper roll can be raised or lowered by screw gears at the right
and left, the arrangement being such that absolutely even pressure is
exerted at the two ends. On the right screw gear there is a notch in the
form of an I, which with every half revolution of the central spindle
moves the length of one tooth forwards or backwards, according to the
direction chosen, so that it is always possible to produce an absolutely
determinable pressure. The rolls, after the setting of the pressure, are
rotated by the handle visible on the right.
This is the whole machine. Its dimensions are determined by the length of
the rolls, and these are chosen as may be needed. One with 40 cm (16 in.)
rolls ought to be sufficient for most work.
It may be possible to rig up existing burnishers or washing mangles.
Whether good results can be obtained therewith, I cannot say from my own
experience.
The care of the machine is very simple; it needs only to be oiled from
time to time.
Although this, or any other suitable machine, is so simple in
construction, and its manipulation is so easy, yet one ought not to
forget that he who uses it ought _not_ to be a machine. The printer must
be very familiar with his press, if it is to give its best. Whoever does
not believe this should ask an etcher, who will soon tell him how much a
good printer can add to a copper-plate print.
PRINTING.—In order to obtain from any bromoil print one or more pulls on
uncoated paper, one requires, besides a printing machine, also—experience.
Before I proceed with the technical description of the whole process it
will be as well that we become perfectly clear as to the conditions under
which transfer takes place.
Bromoil printing has been described as a direct derivative of the
collotype process, and it is. This very close relationship, however,
is merely because of the common property of the exposed and swollen
chromated gelatine film, but does not extend to the method of execution,
in which bromoil printing displays an independent technique. The primary
difference lies in the support: collotype uses a glass plate as the
support for the chromated image, bromoil printing uses paper. This
causes a variation in the subsequent procedure, especially when the
bromoil print is not the final result, but merely the means for making
the transfer. The application of the ink to the swollen gelatine also is
quite different in collotype and bromoil printing, and the transfer of
the ink to the paper by means of a machine is done differently, all of
which are based on the differences of the support.
The bromide print, which is taken as the starting point in bromoil
printing, should be made on a paper as dense in structure as possible;
thick paper, therefore, is advisable, because the film remains damp
longer during the work of pigmenting, and also because all subsequent
manipulations are carried out more easily with thick than with thin
papers. In the collotype process, on the other hand, the chromated film
is carried on glass. When it comes to printing, it is clear, from what
has been said, that the bromoil print not only contains the moisture
which is absolutely necessary in making it, but also that which is in
the fibers of the paper. The whole of this dampness is pressed out of
the paper fibers and the film, during the printing, and combines with
the ink to a kind of emulsion. This _emulsion-like mass_ is brought on
to the paper by the machine, _not the ink alone_, as in collotype, the
chromated film of which holds only that moisture which is requisite for
its swelling, while its support, the glass, can retain no moisture. It
is also the fact that the amount of moisture in the collotype film is so
small that the formation of this emulsion practically does not occur.
From these comparisons and explanations it also follows that the printing
technique of the two processes must differ.
I have dealt with these facts with more completeness because it is
commonly assumed that the printing of a bromoil print must be carried
out like that of a collotype print, and most of the failures result from
ignorance of the differences discussed.
So, while the collotype matrix only gives up its _ink_, the bromoil
matrix gives up a mixture of _ink and water_ to the paper. This emulsion
is so constituted that it readily adheres to the paper where it is in the
finest state of division, but where it is thicker it is more difficult
to made it adhere. In other words: the high lights and the most delicate
and medium half-tones readily transfer to the paper under light pressure,
while darker half-tones and the shadows must receive a stronger pressure,
from which it again follows, that in order to obtain from a bromoil print
a transfer equally good in all its tones, _I must print with gradually
increasing pressure_.
That is the reason that induced me to use a machine, with roll pressure
which can be varied at will, as I have described more fully in the
chapter on “The Machine.”
The procedure in printing must now be very accurately described, and
takes place as follows:
The pressure which the rolls exert on the bromoil print and the paper
as they pass through must be absolutely even, at every point. In order
to make the pressure more uniform than the rolls of even a good machine
can give alone, it is necessary to imbed the print and the paper in
a press-pack. This press-pack generally consists of two pressboards
(hard, thick, glazed pasteboard), at the bottom, an ordinary pasteboard,
a copper-plate blanket, that is a thick felt, and another ordinary
pasteboard. On this pasteboard the bromoil print is laid, and on this
the printing paper. On this printing paper there are now placed in
order another copper-plate blanket, an ordinary pasteboard and finally
two pressboards. Before, however, we pass a press-pack, thus prepared,
through the rolls, it must be explained in fuller detail, which is best
done from an actual example.
Let us assume that we have a print prepared as described in the chapter
“Bromoil Printing,” ready for transfer. Its size shall be 16 × 21 cm (6¼
× 8¼ in.). Our intention is to print this on paper of the dimensions of
30 × 40 cm (12½ × 16½ in.), and to surround it with a plate mark. As the
size of the paper is 30 × 40 cm (12½ × 16½ in.), the four pressboards,
the three ordinary pasteboards and the two copper-plate blankets should
be cut exactly 32 × 42 cm.
The two pressboards are accurately superposed on a table and then the
pasteboard and the blanket are placed on top. On the last, as already
stated, another pasteboard is placed, which must, however, be previously
marked with pencil guide lines, for on it are to be laid the bromoil,
the paper and the plate-mark pattern. As we wish to surround the print,
which is 16 × 21 cm, with a plate-sunk mark, we must cut a sufficiently
large pressboard to impress this mark. Let us say we wish to surround our
vertical print with a margin which shall be 1 cm (⅜ in.) wide above and
right and left, but 2 cm (¾ in.) below, then we must cut the pressboard
18 × 24 cm (7½ × 9½ in.). When we have done this we mark on it with a
pencil exactly the position of the 16 × 21 cm bromoil print. Now we find
on the 32 × 42 cm pasteboard the position at which we wish to have the 18
× 24 cm pressboard just cut (as a rule this will be a little above the
center), and fasten it there very lightly with library paste or mucilage.
The 18 × 24 cm pressboard now lies on the 32 × 42 cm pasteboard. As the
size of the paper is only 30 × 40 cm, this will leave a margin of 1 cm
on all sides, and this future position of the paper should be accurately
marked with the pencil on the pasteboard. Extreme care having been taken
that all the lines are parallel and the measurements correct, we can now
place in the press-pack the bromide print and the transfer paper, and
proceed to print.
[Illustration: FIG. 2
A = pasteboard
B = the plate-mark pattern
C = the location guides for the transfer paper
D = the location guides for the bromoil print.]
The marking of the individual layers may be done very simply and
accurately if it is carried out as shown in the accompanying diagram.
This marking of the layers has also the advantage that we may use it for
all sizes with slight alterations for individual cases. The lay-out is
very easy. The pasteboard which carries the plate-mark pattern is cut
accurately right-angled and must be about 2 cm (¾ in.) larger all around
than the transfer paper that is to be used. On this board we now draw,
exactly 2 cm below the upper edge, a sharp line with ink that will not
smear, such as waterproof drawing ink, stopping exactly also 2 cm from
each edge. Then this line is bisected and the center point marked zero;
right and left of this zero point we now draw equally distant upright
lines, about ½ cm (³⁄₁₆ in.) apart, which are numbered 1, 2, 3, ... to
the ends of the line. Like divisions are drawn on the plate-mark pattern,
or if this is not to be used, at the place it should occupy. The bromoil
and the transfer paper are now laid down with the help of these lines so
that the upper corners are equidistant from the zero point, which can
be very easily done. These location guides are also very convenient in
combination printing.
We now have lying in front of us one on top of each other: two
pressboards, an ordinary pasteboard, the copper-plate blanket and the
pasteboard with the plate-mark pattern and the marks for locating the
paper.
Now the bromoil print is lifted from its pad by passing a knife under
its edges, and laid carefully with its _back_ on the worker’s left hand.
Thus the print can be laid down face up _without danger of damage_ on the
plate-mark pattern, adjusting it by the position guide before sliding
out the hand, all without touching the face of the print. Great care
must be taken that the print lies absolutely flat. It will adhere to
the pasteboard without any aid except its own moisture. Now we take the
printing paper, hold it at the upper third of its surface with the two
hands and bring the upper edge to coincide with the pencil lines on the
pasteboard which carries the plate-mark pattern, taking care that it does
not touch this pasteboard. When the edge of the paper and the pencil
lines coincide, the paper is carefully allowed to drop into position from
the top to the bottom. It now lies on the bromoil print; now, holding
it _very gently_ on the bromoil print with one hand, the previously
prepared copper-plate blanket is spread out with the other hand over
the paper and pasteboard, and the two pressboards are placed on the
cloth in the same way. Care should be taken that the whole arrangement
is fairly evenly made up, so that none of the edges of the boards or
blankets project beyond others. If this precaution be omitted it may
happen that the transfer paper is squeezed into wrinkles running from the
edges to the middle, which may even encroach on the print itself. These
squeezed-in wrinkles, which, if the pressure be great, may appear like
sharp cracks, make the print useless. This whole manipulation is rather
difficult to perform at first, but it is learnt very rapidly, especially
if the first experiments are made with a damp sheet of paper the size
of the bromoil print instead of the print itself, and one thus becomes
expert.
When the press-pack has been made up in the above-described manner,
it should be taken firmly in both hands, so that nothing can shift,
and the upper edge placed on the machine table and guided between the
rollers, the separation of which must be such that they just grip the
pack _without exerting any pressure_. This separation must be determined
by experiment. The pack should then be gently drawn through until about
4 cm (1½ in.) of its lower edge remains protruding. Shifting is then no
longer possible. The rolls should now be tightened, for which purpose
the central spindle should be given six to eight _half_ revolutions.
The exact pressure cannot be prescribed, but it will always be better
to begin with light pressure. The handle is again turned and the pack
drawn through the press, until its upper edge sticks out about 4 cm (1½
in.). This process is repeated four times—twice in each direction.
If, after the fourth revolution, we carefully lift up the upper layers
including the paper—obviously while the lower edge is still held fast
for about 4 cm by the rolls—we can inspect the _first impression_ and
will see that the high lights and fine half-tones have already given up
all their ink, while the deeper tones still look very flat. The paper
should be allowed to drop back again gently, and then the other layers.
Then the pressure is increased by giving the central spindle about three
or four half-turns, as, after the first impression, there is little
danger to either bromoil or transfer through heavier pressure, and the
pack is again passed through the rolls, but only twice, once in each
direction. If the print is now examined again it will be found that the
full half-tones and the lighter shadows are already transferred, but
that the deep shadows do not appear in full tones. Then the printing is
repeated with still greater roll pressure, three or four more half-turns
of the central spindle; again the pack should only go twice through the
rolls. Another examination should now show the print in full vigor in all
its details. If, however, it should happen, especially when using rough
papers, that the shadows do not yet appear quite deep enough, one should
print again twice with increased pressure. All the ink which was on the
bromoil print will now be transferred to the paper; if the printing
was carried out properly the bromoil will look as if it had not been
pigmented at all.
_It should never be forgotten that the rolls ought never to be so
strongly screwed down that they can only be started by great effort; they
must always move easily, and with little muscular effort._ _Repeated
slow_ passage of the press-pack through _moderately tightened rollers_
is always _more advantageous than a single printing under very heavy
pressure_.
Heavy pressure not only endangers the bromoil, since the gelatine film,
especially in the lights, adheres to the paper and tears when removed,
but the transfer also, because the water, pressed out quickly and with
great force, is deposited in the ink in the form of fine globules. After
evaporation, which takes place very quickly, these places show curious,
light, circular or elliptical spots, which produce the general impression
of a picture painted in the pointillist manner—an undesired effect which,
however, may occasionally be satisfactory.
It is very advisable to turn back the central spindle before finally
taking the press-pack out of the machine, as otherwise one may uselessly
and prematurely ruin the components of the press-pack.
The bromoil can be immediately immersed in water and again pigmented—as
was done at first, or with different ink. This process may be repeated
until the paper breaks down, with careful treatment in printing and
suitable stout bromide paper, up to twenty times.
If the pressure of the rolls was too great, then the film shows blisters,
which at first, and if they only appear here and there, are harmless,
even when they occur on important parts of the print. If their number
increases, however, it is better to make a new bromoil.
If the bromoil is to be kept for future work, then it should be allowed
to become bone dry, in order to dissolve off any grease with benzol or
other solvent, exactly as is done with a bromoil print in defatting.
Prints thus treated can be used again after any lapse of time.
This method of printing is proper for either monochrome or polychrome
impressions.
In conclusion the fact may be mentioned—first published in France, I
believe—that bromoil prints, which in the course of making have been
soaked in ammonia water, can be more easily transferred, and that there
is less danger of the bromoil print and the paper sticking together, even
with very strongly absorbent papers.
Robert Demachy has stated that transfers can also be prepared by
removing the ink, not by a press, but with a solvent, such as benzol, by
moistening the paper with this solvent and then bringing it into contact
with the pigmented bromoil. My experiments in this direction could not
be brought to a conclusion, as at the time I undertook them a suitable
solvent was not available. I had only succeeded in determining that
it is very important that the bromoil print should be allowed to dry
thoroughly—from six to eight hours—and that then a less volatile solvent
than benzol, such as heavy benzine, or best of all, gasoline or petroleum
ether, can be used. If the bromoil print is laid on a sheet of paper and
moistened with this, then pressure in a printing frame is sufficient in
order to obtain a transfer. A machine is not required.
The pictures which I have obtained in this way have not been
satisfactory, up to the present time; the cause of the failure obviously
was that I lacked experience as to the necessary degree of moistening and
the duration of contact. As stated, for lack of materials, I was obliged
to discontinue experiments.
COMBINATION TRANSFER.—The process just described permits the transfer
of all that was in the bromide print. If, however, it is a question of
improving the inadequate gradation of a bromide print from a long-scale
negative, we must use other means. Bromide paper has only a limited
scale of tones and therefore cannot reproduce the full modulation of
a negative of full gradation. If the details in the shadows are to be
retained in such a case, then the high lights will appear bare; if
well-modeled high lights are desired, then we risk blocked-up shadows.
This difficulty has been largely overcome by Dr. Emil Mayer, by the
introduction of a combination printing process for bromoil transfer,
of which full details will be found on page 125. He starts from the
above-mentioned fact that bromide paper does not reproduce the whole
scale of tones of the negative, when this is too long, and therefore
divides the tones of the negative into two parts by exposing one bromide
print only for the shadows and the adjacent half-tones, and a second
merely for the high lights and the lighter half-tones. He then transfers
these two constituent prints in superposition and thus obtains the full
gradation of the negative. It is thus possible therefore to lengthen the
scale of tones _of the negative_. If, however, it is merely desired to
extend the scale of tones of _the bromide print_, then it is sufficient
to make the combination transfer from one print only, which must,
however, be prepared in a way differing slightly from the usual.
I will not repeat here the theory of the two kinds of combination
transfer, which may be found in an earlier chapter by Dr. Mayer (page
125), but in giving my own instructions for the practical performance of
the process, I have essentially adhered also to Dr. Mayer’s instructions,
with his full permission.
COMBINATION PRINTING FROM TWO BROMOILS.—It has frequently been pointed
out in the literature of the gum process that the best positive
transparencies may be obtained from a _long-scale_ negative by making
_two_ positives from the one negative and then bringing these two
positives into superposition; for this combination, one positive must be
_fully exposed_ and _developed soft_, the second, on the other hand, kept
_hard_ by a _very short exposure_ and _full development_. If these two
positives are laid film to film, “there is obtained,” as von Hübl wrote
as early as 1898, _in applying this method to gum printing_ (see Eder,
_Das Pigmentverfahren, der Gummi-, Oel- und Bromöldruck_, Halle, 1917),
“a result which often surpasses, in truth and fidelity to the original,
a normal print from the negative. In such a combined print the high
lights are derived from the short, the shadow details from the long-scale
negative; the two images supplement each other and reciprocally increase
the brilliancy. It is also possible to make good defects in the negative
or the printing process.”
This same principle is used in our process, although not exactly as in
gum printing. The process itself is not difficult. It is necessary to
make two perfectly registered bromide prints, which is most easily done
by always placing the printing frame in the same position in filling,
as for instance by fitting the same two sides into a rigid iron angle
fastened on a drawing board, or, in enlarging, by using a right angled
piece of strong, black card glued to the enlarging easel, and fitting the
paper into this angle. I have prepared a simple and absolutely certain
arrangement for securing registering prints by having a beveled-edge
rectangle cut out of sheet iron 2 mm (⅟₁₈ in.) thick, the opening being
somewhat smaller than the bromide paper. Thus, for instance, for 24 × 30
cm (9½ × 12 in.) paper, the cut-out is only 23 × 29 cm (9⅟₁₆ × 11⅜ in.).
_Care must be taken in this work, however, that the bromide paper for
both prints is taken from the same packet_, since only identical papers
expand absolutely equally in the baths and contract equally in drying.
Although the paper used by the manufacturer may be of the same quality,
yet it may not always be handled exactly the same in coating, so that
a registration of the prints may not be possible when one uses paper
prepared at different times.
The _first_ print is now _very fully_ exposed and developed soft, just
long enough so that the high lights and upper half-tones are well brought
out. When this is attained, development is stopped _without paying
attention to the shadows_, which will be full of detail, but weak.
The second print is exposed as briefly as is required for the perfect
reproduction of the shadows, with the use of a hard-working developer.
As soon as the shadows appear in full depth, the print should be rinsed
and fixed. The print then shows, besides the shadows, only the transition
into the half-tones. It is not easy to give more accurate instructions
for the preparation of the bromide prints, as the work must be carried
out differently according to the negative. Only, _as a hint_, and nothing
more, it may be stated that in a print where exposure of about twelve
seconds was required for the complete printing of the high lights and
half-tones, the shadow print needed only about three seconds, or about
one-fourth the exposure. This ratio obviously alters in accordance with
the depth and quality of the shadows in the negative, and must be left to
the feeling and experience of the worker. When the two prints have been
developed, fixed, washed and dried, they should be tested for equality
of size by measurement with a millimeter scale. Then rule pencil lines
around the edges of the prints very exactly, and treat them in the usual
way in the bleaching bath, the second fixing and washing. When thoroughly
dry the pictures should be cut along the pencil lines with absolute
accuracy, and their registration again tested. It is advisable to write
on the back before bleaching “high light print” and “shadow print.”
Pigmenting is effected as usual. Practically, one should always begin
with the _high light print_, as this is intended to give the finest
modeling in the high lights and half-tones, while the shadows are
treated so that they show all the details, but no depth. This order of
working leaves one absolutely free in the treatment of the fine tones,
independent of the depth of the shadows. These depths are produced in
the transfer in any desired strength by means of the second bromoil. If,
however, the work is started in the reverse way, by printing the shadows
first, then the half-tones and high lights must be adjusted to the
existing depth, which may produce a dislocation of the tone values, even
to a destruction of the whole desired effect. The best way is therefore
to direct the whole attention in the first place to the lighter parts of
the picture, and to suit the shadows to these.
When the _high light print_ is completed as desired, the transfer may be
made. The bromoil print is placed on the location guides, described in
the previous chapter on “Printing.” Then the transfer paper is placed
on its guide and pencil lines very carefully drawn across the edges of
the back, on to the pasteboard. Then it is printed. The picture will now
appear in full beauty as regards the lighter tones, but obviously as a
whole will be flat, since the shadows are grey and without depth.
Now we proceed to the working up of the shadow print, which when complete
should appear absolutely bare of high lights and _light_ half-tones. No
protective measures to prevent the sticking of the non-pigmented parts
to the transfer paper are necessary, as these white portions of the
shadow print are already covered from the first transfer. The print is
now placed exactly on the marks made on the plate-mark pattern before the
first transfer, the first transfer also brought into the same position by
the marks on its back and their prolongations, which is very simple in
practice, and is then printed. The transfer now shows the full gradation
of the negative, or the sum of the gradations of the two bromide prints,
which, however, will be enhanced in effect by the plastic softness
produced by the double printing. If it should be necessary to strengthen
any part of the print, to deepen any shadow, we can again pigment the
necessary portion of the proper bromoil and transfer it to the picture by
a third printing, for it is thoroughly practicable to superimpose as many
impressions as may appear necessary from an artistic standpoint.
This method of combination printing from two bromoils is the best
attainable result in the present state of the art, but contains also the
germ of future developments, especially as regards color photography,
which problem appears to me to be most easily solvable in this, purely
artistic, way. Only it is necessary to find an artist who can conduct the
various printings with such fine color sense that the final result will
actually produce the impression of a _work of art_ in color, not that of
a colored photograph, which has unfortunately hitherto been the case with
all experiments in this direction. This is obviously nothing more than a
hope for the future. For the present we must content ourselves with what
has actually been attained, which is no more and no less than to bring
us close to our aim, ability to consider and use the photographic plate
merely as a foundation for our graphic art.
COMBINATION PRINTING WITH ONE BROMOIL.—It is frequently not easy to
reproduce perfectly in the transfer the whole scale of tones present in
a given bromide print; or at least in many cases a high degree of skill
must be employed. It is consequently often very much simpler to make _two
transfers_ from the _same_ bromoil, one being inked up for the light
parts, while the other is used to fill out and deepen the shadows.
The practical execution of the process is as follows: the bromide print
is swollen in the normal way and pigmented with a _soft ink_ suitable
for the high lights, the shadows being very lightly inked. The transfer
obtained from this bromoil print shows all the details in the high
lights, with grey shadows. The print is now immersed in cold water to
swell again and then inked up with a _hard ink_, so that only the shadows
and the adjacent half-tones are fully worked up. This print is now
transferred to the same paper, so that a transfer is obtained in which
the scale of tones of the bromide print is considerably lengthened.
A second method of making two transfers from one bromoil is first to
swell it normally, then ink up thoroughly and transfer. It is then highly
swollen with ammonia and the shadows only treated with hard ink. The
result of the second transfer on the first one is again full gradation
in the print. This method, however, is not very advisable, as the print
cannot be used again if the second transfer is not successful. It is
better to adhere to the first method, and preferable to use two inks of
different consistency rather than two differing degrees of relief.
If, however, the combination transfer from a single bromoil is to give
the best possible gradation, the exposure and development of the bromide
print must be properly done, the process being essentially that of
Benndorf, referred to on page 143.
The bromide print must be fully exposed and developed very soft; the
image then seems flat, and yet every gradation of tone present in the
negative is actually shown in the bromide print. If a print thus prepared
is treated with inks of two consistencies, the best results are obtained.
THE VALUE OF COMBINATION PRINTING.—With the aid of combination transfer
it is possible to solve problems in the bromoil printing process, which
were hitherto unsolvable, and Dr. Mayer correctly remarks at the end of
his treatise: “The transfer process has advanced to the first place and
in future in the hands of the expert, bromoil printing is likely to be
considered as a process of secondary importance.”
I was early convinced that transfer would replace bromoil printing and am
absolutely of the opinion that combination transfer will do its share in
making my opinion universal. Still I do not believe that it is necessary
to use combination printing in all cases. I would especially warn the
beginner against using it exclusively; he should rather endeavor to make
simple transfers starting from a perfect bromide and a perfect bromoil
print, for by this means he will attain much more certainty in printing
technique. Only when he has absolutely mastered this technique, should
he begin experiments in combination transfer from one bromoil.
_Every worker should endeavor to use the technique of combination
transfer for the execution of an artistic idea, rather than for
overcoming technical difficulties in single transfer._
Then it will, however, always give excellent results. Aside from the
solution of such problems as views from a dark space into a brilliantly
lighted distance, or pictures of falling water in conjunction with its
dark surroundings, etc., it will be especially useful to the portraitist
in treating his backgrounds.
Combination transfer from two originals will, however, be most valuable
artistically, when there is a question of combining sharply defined parts
of a picture with softer parts. Thus, for instance in a landscape, we
may make a sharp print and, by the use of bolting cloth, one with soft
outlines; the parts which it is desired to emphasize will be worked up on
the former and artistic softening added from the latter.
Briefly, the possibilities are so many that they can hardly be indicated,
not to speak of describing them in full. This is, besides, hardly
necessary, for the worker who has reached full mastery of combination
transfer is necessarily so far advanced artistically, that he will find
out for himself all that is necessary.
RETOUCHING AND WORKING UP.—A good bromide print can only be prepared from
a good negative. So says the expert bromide printer. The bromoil printer
_requires_ a faultless bromide print as the fundamental condition.
The transferrer, finally, will not use an imperfect bromoil print for
transfer.
I belong to the school which would produce a photographic picture only
by purely photographic means, without, however, being too orthodox; I
would not, therefore, repeat the whole laborious making of a bromoil
print, because I might not think it photographic to spot out with
water-color a small spot the size of a pin’s head, or to remove a small
particle of ink with the etching knife. This is actually not retouching,
but there are people who consider these changes as such.
By retouching I mean the justly condemned excessive “working up” of a
_positive_ print, that is a change of values on the finished print. That
should not be done.
Bromoil printing is still that exquisite process which permits the
correction of false tones, the suppression of undesirable and the
emphasis of the most characteristic details in the most extensive way
_during the work_.
I consider it objectionable to leave all faults which occur during
the long process of picture making, for the sake of convenience, to
be improved on the positive print. But if it does become necessary to
use retouching on the transfer, it can be done with a soft eraser. An
excellent means of working up larger areas has been described by Dr.
Mayer (see page 123), which consists in working on the transfer with
the same brush and the same ink as was used in making the bromoil. Thus
clouds may be imitated by pigmenting the white surface and then working
in the clouds with the eraser, etc.
Since, however, this and other improvements can be carried out, not only
as well, but even better on the bromoil print itself, it is advisable to
do so much with the brush that nothing remains to be done on the transfer.
DRYING.—As soon as the transfer leaves the press, it is finished, but as
the ink is very easily smeared it is advisable to leave it exposed to
the air for two or three days. After the lapse of this time the ink has
usually hardened.
Very heavily inked prints require from eight to ten days to dry and may
be considered as absolutely dry when the oily sheen which can be seen
immediately after printing, especially in the shadows saturated with ink,
is replaced by a velvety, perfectly matt surface.
Retouching can be begun about one or two hours after it has left the
machine.
A transfer should not be mounted, for it looks best as it is, if the
margin is sufficiently large.
CONCLUSION.—The technical difficulties of making a good transfer are
not small, and to overcome them requires a certain degree of skill in
the worker, which other processes do not require to an equal degree. By
“workers” I mean especially amateurs, not those professionally skilled
in the graphic arts. After overcoming these difficulties, caused chiefly
by the materials, there is a certain feeling of satisfaction in having
actually produced a work of art. By using the different techniques
of bromoil printing: soft ink, hard ink, sketch, and coarse grain,
one can obtain transfers of such beauty as may confidently be said
can be attained by no other process. There is unlimited possibility
of variation; and this alone assures the bromoil transfer process
preëminence over any other method of printing.
That a transfer can be used as a basis for working up with pastel and
water-color need only be incidentally mentioned, because such work
is outside of pure photography and it is unnecessary to express an
opinion as to the artistic value of such productions in this place. The
photographer should always adhere to the fundamental law: Do not forsake
photographic methods.