THE PREPARATION OF BROMOIL INKS
BY EUGEN GUTTMANN
Everyone who devotes himself to the higher aims of photography, and
studies the works of painters, must learn to see with the artist’s eye if
he will apply his knowledge in pictorial presentation of his subjects.
In the same way the bromoil printer should become more familiar with
the working tools of the painter, and especially with the most valuable
material at his command, the ink, than has hitherto been the case.
When we look back on the history of painting, we note the often-mentioned
fact that not only the old masters of all schools, Italian, German and
Dutch, but also the later generations till about the middle of the last
century, ground their own colors. They did this not merely to be assured
of the most perfect purity and thus absolute permanency, but also because
they wanted to obtain the greatest possible brilliancy.
As regards the purity of the materials used—the colors and the
mediums—there is no doubt that to-day, thanks to the high perfection of
manufacturing methods, this can usually be depended upon; but as regards
the brilliancy, no positive instructions of any kind for obtaining this
have come down to us. The painters took their secrets with them to the
grave. But as the result of exhaustive research, together with advances
in the manufacture of colors, we can assume with some certainty that
the masters of past times attained _vigor in their colors_ chiefly _by
the finest possible grinding of the colors and by a relatively small
addition of medium_. “_It may sound paradoxical_,” says Professor Th.
Petruscheffsky in one of his treatises on the technique of painting,
“_but it is, however, true, that in oil painting oil should be avoided as
much as possible_.”
The old masters knew this and acted accordingly, and the modern
manufacturer also knows it, and replaces _any excessive quantity_ of oil
in the medium, which is mixed with the pigments to bring them into a
paintable form, by other substances, for instance turpentine, and certain
resin solutions, which have no binding properties; during the work these
substances evaporate and leave behind the color with very little medium.
These facts the bromoil printer must know, for he should also use colors
from which he can get the very best possible results.
The ink is one of the most important parts of his equipment. This fact
was fully recognized by English, French, and German manufacturers, and
inks were obtainable that left nothing to be desired. At the outbreak
of the war the position of affairs was immediately altered. It was not
possible to use English and French sources of supply and the German
supply gradually failed. What was furnished as ink for the oil process
was suitable for anything else but that—a soft, smeary and smearing mess,
which did not permit any finer working up of the picture, and required so
high a relief that individuality in the work was excluded.
These conditions induced me to try and prepare the necessary inks
myself, and after many trials and exhaustive experimental study of the
manufacture of artist oil colors I finally succeeded in reaching my goal.
INKS AND BRUSHES.—My starting point was a great desire to make a _hard
ink_, since I recognized that this consistency was the necessary starting
point to be able to use any degree of relief. I further desired to attain
a mixture of color and medium which should be as perfectly homogeneous
and as fine as possible, and moreover to provide a palette, which should
not only satisfy all requirements of the bromoil printer, but also give
him only fast colors, perfectly suitable for the transfer process and
soluble in benzol.
Command of a _hard ink—which can be suitably softened to meet any
need_—is very necessary to the bromoil printer, if _clean shadows_ are to
be obtained. As already mentioned, it has long been known among painters
that the colors appear purer and more luminous when they contain as
little medium as possible. In order to be able to apply such stiffly
ground colors, the painters use bristle brushes, which do not produce
the same results as hair brushes. Naturally there is nothing to prevent
the bromoil printer from using _bristle brushes_, only they must fulfil
certain requirements. The literature of bromoil printing gives many hints
on this point, but I have not been able to locate a practical use of
these brushes. Some years ago I had made, by a manufacturer who makes
excellent hair brushes for our process, bristle brushes in stag’s foot
shape. The result was extraordinarily gratifying. These brushes do not
drop their bristles nor do they suffer from the troublesome breaking off
of the points, they do not pick up the dust and do not smear even when
very soft inks are used, because the bristles, unlike hairs, do not cling
together. They can be easily and thoroughly cleaned and are obviously
very lasting, and in addition cost only a fraction of what must be paid
for really good hair brushes.
As regards the size one is not limited, as with the hair brushes, to
small sizes, since the hog’s bristle brushes can be made of any desired
diameter, even 10, 15 or 20 cm or more (4, 6 or 8 inches or more) so that
the working up of large prints is considerably facilitated.
Two conditions must, however, be carefully observed for good results.
First, these brushes must actually be made from the _very finest cut_
bristles and, before they are used, they must be _repeatedly and very
thoroughly cleaned_, because they are very dirty when purchased.
The principal advantage of these brushes is that they _enable one to
use considerably harder inks_ than is possible with hair brushes, which
results in _much greater clearness of the shadows_. When this clearness
of the shadows is obtained, one can always use a hair brush for working
up the finer half-tones and high lights. This is, however, not necessary,
at least in the majority of cases.
I have _not_ noticed any disadvantage in the use of these brushes; the
gelatine has never been pierced, even in the highest reliefs.
Although I am averse to anything that may smack of advertising, yet
I will state here the source of these brushes, because the expert
manufacture of these tools, so important in our handicraft, is not found
everywhere in equal perfection, and because I believe that it will be of
considerable service to those wanting brushes. The brush manufacturer is
Magnus Bühler, Wien VII, Breitegasse 4, Austria.
[Illustration: FIG. 3]
I might add a word here as to the cleaning of brushes in general, whether
hair or bristle. It is usually recommended to wash out the ink with
benzol or similar solvent, carbon tetrachloride, trichlorethylene, etc.
A really thorough washing is never obtained with these; and the brushes
almost always give up a greater or lesser quantity of small particles
of ink to the new print when used again. The following process is much
better. The brush to be cleaned should be dipped into lukewarm water and
then rubbed firmly on a piece of ordinary soap (soft soap is better), so
that it takes up as much soap as possible. Then the soap should be worked
up into a lather on the palm of the hand and washed off. If this is
repeated a second time and the brush is then rinsed two or three times
in lukewarm water, repeatedly changed, the brush will be far cleaner
than can be obtained in any other way. After it has been well rinsed and
shaken out it should be put into its tube and hung up by the handle in a
place free from dust to dry (see Fig. 3). This vertical position has the
effect of facilitating the draining of the moisture from the quill base,
where it otherwise collects. Any brush thus treated will be dry in a few
hours. The finest hair brushes are not damaged at all by this treatment,
which is commonly used by painters.
THE PREPARATION OF THE BROMOIL INKS.—The preparation of the bromoil inks
is very simple. The following are necessary:
Linseed oil varnish of the thickest consistency;
Powder colors;
A rubbing plate;
A pestle;
A springy spatula (palette knife);
A stiff spatula, the so-called ink knife (putty knife).
The following sections will give the necessary information as to the
properties and nature of each item in this small arsenal.
THE VARNISH.—Only such varnish should be used as is prepared from linseed
oil and chemically pure. Its color should be light to brownish-yellow
or at most reddish-brown. Dark brown or blackish-brown varnish points
to adulteration. The smell is that of linseed oil and is not exactly
pleasant, but it should not smell badly. In the latter case one may
reckon with certainty on the addition of fish or resinous oil. One
principal requisite of this varnish is that it should be absolutely
_clear_. The varnish is produced of various consistency, from quite
fluid to quite viscous, and _this is one of the principal properties, to
which the bromoil printer must pay special attention, for every degree of
consistency demands and must have only one definite quantity of color_,
otherwise the resultant ink will not satisfy the desired end. More as to
this later.
I used for all my experiments and later for all actual mixing the linseed
oil varnishes, No. 1 and No. 2 (chemically pure) of the firm of Kast &
Ehinger, of Stuttgart, which have always given me excellent results,
without failures. Excellent also is the somewhat less stiff “collotype
varnish.” But any other varnish, if it only has the right consistency and
is not adulterated, must also give good inks, though great care must also
be taken as to clearness and color.
Warning should be made against oils similar to varnish, which can be
recognized by a cloudy appearance and a very unpleasant rancid odor. They
harden very quickly and thus become useless and are very costly.
The stiff varnish is very viscous, like thick syrup. In the cold it
thickens with the formation of a thin skin on the surface. On a hot water
bath, it again obtains its original character. Well corked up, good
varnish will keep for years; it even becomes better by long storage. It
is most convenient to fill the varnish into small wide-mouthed bottles,
holding from 20 to 40 g (about an ounce), with ground-in stoppers, as
one can note its appearance at any time through the glass. In taking
the varnish out of the bottle, care must be taken that none gets on the
inside of the neck, or else the bottle can only be opened with difficulty
through the varnish gumming it up.
POWDER COLORS.—Only such colors should be used as are fast both to light
and air. The following may be selected with absolute certainty:
For black: bone black, ivory black, crayon sauce;
For brown: burnt umber, burnt sienna, burnt dark ochre;
For yellow: cadmium, light and dark, yellow ochre, light and dark;
For red: English red, light and dark, Indian red;
For blue: indigo, ultramarine, cobalt blue;
For green: cobalt green, light and dark, Bohemian and Veronese earth;
For white tones: zinc white.
The bromoil printer obviously does not need all these. One representative
of each group will be quite sufficient, and I should state that when
colors are obtainable in both light and dark shades, the light one should
always be chosen.
The colors must be very finely ground; it will not be necessary, or
only exceptionally, to prepare the powder colors oneself, for they can
be obtained commercially in every high grade store dealing in painters’
materials. If, however, this becomes necessary, then the lumps of color
should be crushed on a stone or glass with a flat muller, and the coarse
granular masses thus formed kneaded with a little water, or, better
still, some alcohol and then thoroughly ground. The mass should be
allowed to dry thoroughly and the process repeated two or three times.
_The finer the powder is rubbed up in this way the finer the tone it will
give._ The _coarse_ color powders, often found in drug stores, are not
suitable for our purpose; they are used more for industrial purposes.
_Aniline_ colors, or those brightened with anilines, should be absolutely
avoided, as they stain the gelatine and thus spoil the print. On the
other hand I call the attention of all bromoil printers to the _pastel
colors_, which can be used with excellent results. They offer many
advantages over the powder colors, since among the hundreds of color
shades, in which they can be obtained, it is easy to choose that which is
most suited for the subject. The tints are ready to use, while with the
powder colors the desired tint can only be obtained by mixtures. These
colors have the further advantage of covering much more strongly, even
to obtaining brush texture; they are somewhat more difficult to apply to
the print, because of the fact that they are mixed with a medium which is
from its nature not so well adapted to our process. Those, however, who
have well mastered the brush technique, will easily overcome this small
hindrance.
If the pastel colors are used one should only take those of reliable
manufacture, such as those made according to Mengs’ formulas, which are
everywhere obtainable under the name of _Meng’s pastel pencils_, though
this does not mean that those of other makes will not give excellent
results.
THE RUBBING PLATE.—For this we use a thick plate glass slab, ground on
one side, about 15 by 20 cm (6 × 8 in.).
PESTLE OR MULLER.—A pestle of glass is the best. The head must be round,
not flattish, and have a matt surface.
SPATULAS.—It is necessary to have a flexible spatula (palette knife)
about 1 cm (⅜ in.) wide and a stiff one, an ink or putty knife, about 4
to 5 cm (1½ to 2 in.) wide.
Now that we have become conversant with all the necessary materials, I
come to the:
PRACTICE OF INK GRINDING.—As I have mentioned above, the purpose of the
work is to obtain an ink of as stiff a character as possible. To this
purpose, after the vessel in which the varnish is kept has been allowed
to stand at least 10 minutes in hot water, or an hour in winter, we
remove from it by means of a wood or glass rod a very small quantity of
the varnish, spread it on a glass plate and rub it with the pestle so
that it covers a surface of 3 to four qcm (½-¾ sq. in.). To the varnish
thus spread out we add with the flexible spatula a small quantity,
about as much as will lie on the end of a pocket knife blade, of the
powder color and rub it with the pestle until certain that the color is
absolutely mixed in. If too little color has been taken, more should be
added and rubbed again until a firm doughy mass is obtained which has a
_slaty and not oily gloss_, and can scarcely be worked with the pestle.
Now with the springy spatula the whole ink mass is pushed together from
the edges to the middle to make a little heap, and the ink that remains
on the pestle scraped off and added to it; the whole mass should then be
again worked up with the pestle and this procedure repeated two or three
times. Then the ink is ready. It must be so hard that a brush set into
a small quantity of the ink that has been taken from the heap with the
stiff spatula and spread out in a thin film, neither takes up the ink nor
gives it up again to white paper. In order to make it fit for use, one
must add to this thin film _one_ small drop, not more, of pure linseed
or poppy oil, petroleum, light copper-plate printing varnish, or medium,
and mix it well with the ink with the stiff spatula. Petroleum can be
highly recommended for the softening medium. One can use the ordinary
lamp petroleum, but the so-called purified petroleum is better. It ought
only to be added to the ink drop by drop. Now the brush will take up and
give up the ink. If it should not be sufficiently soft, the procedure
should be repeated, but always carefully, so that too much linseed oil is
not added and thus the ink made too soft. If we use the pastel instead
of the powder colors it is not necessary to break these up first. Small
pieces broken from the pencils dissolve readily in the varnish. It would
seem permissible to assume that the whole work of dilution with linseed
oil could be saved by not adding so much color to the varnish, but by
proceeding with the inking-up as soon as the ink is taken up by the
brush, _but this is not the case_.
As I have stated above under “Varnish,” every degree of consistency of
the varnish requires a definite quantity of color. If one adds too little
color, the paste will be too soft for bromoil printing, and cannot be
spread. Too much color is hardly possible with the stiffest consistency;
the limit lies when the color no longer dissolves in the varnish. Too
little, on the other hand, results in the ink smearing on the print.
_It is, therefore, absolutely necessary_ in using very thick _varnish_
to _absolutely saturate_ it with color. _Not going far enough in this
direction_, or the omission of the preliminary warming of the varnish,
_are the only sources of failure_. In working with varnish of lighter
consistency, it will be necessary to stop the addition of color as soon
as the slaty gloss appears.
If the grinding of the ink were to require as long as it takes to read
this description, the waste of time would be considerable. Actually the
whole work may be carried out in two or three minutes if one uses the
methods suggested, and after a little experience is gained, which soon
comes after a few trials. Long before the water for the bromoil print is
hot, the ink will be ready.
INK MIXING.—As it is not always possible to use existing colors, and it
is necessary in many cases to alter the shades for artistic effects, the
basic colors must be diluted with other colors. This can be effected in
many ways, best by adding another color to the predominant color powder
during the mixing. _Bone black_ is specially valuable for this purpose.
This is by itself an unpleasant color, for it is a discordant brown-black
which can hardly be used alone. If other colors, however, are added to
this bone black it produces beautiful tones. Thus, for instance, the
addition of a minimum of blue (indigo or ultramarine) gives a _deep,
velvety black_; if a _little_ more blue is added, we obtain a beautiful
blue-black. A little bone black mixed with burnt umber gives a fine _warm
black_, and so on.
The tone of crayon sauce is especially beautiful, if it is used without
the addition of any other color, and especially that quality obtainable
under the name of _Sauce Velours_ is particularly excellent.
Another kind of color mixture is that in which black is taken as _the
fundamental color_ (which is desirable when it is not desired to mix up
ink for each print) and then instead of diluting the _stiff_ ink with
linseed oil or other diluent, an ordinary good copper-plate ink or even
ordinary _oil colors_ are used. By this method of working I can shade
and soften in one operation, and it is highly advisable to use it when
it is desired to obtain different tints easily. The method of mixing is
very important and I will therefore give some examples. If to the stiff
black ink (bone black), I add a little indigo _oil_ color, I have at
once a deep black; the addition of vandyke brown or burnt umber gives a
magnificent brown; a fine dark green is obtained with light cadmium; this
dark green becomes blue-green when I add a little indigo. An admixture
of caput mortuum shows violet tones; red tube colors, such as Indian or
Pompeian red, ochre, etc., give various reddish brown nuances. These
additions can be varied in manifold ways, dependent only on what tube
colors are at hand. It is strictly necessary, however, that only the
least possible quantity of tube color should be added, about as much as
the head of a good-sized pin, to keep the ink from becoming too soft and
going beyond the desired tint. When a suitable shade has been attained,
all further dilution must be effected with linseed oil, petroleum, etc.
When I specially recommended the Mussini or Fiedler colors, it was
because they are prepared with resin oils and are therefore specially
suitable for our purpose. But all other _good_ oil colors can be used.
When I write briefly only _oil colors_, I mean obviously _artists’ oil
colors_, and not others which may be used for other purposes than for
artistic painting.
Finally the black may be diluted with linseed oil to the usable
consistency of hard ink and also diluted on another part of the palette
with oil color or copper-plate ink of another shade to the consistency of
a soft ink, and then both colors may be mixed either on the print or in
the brush.
Very fine gradations may also be produced as follows: the bromoil
print is pigmented as usual to obtain as _clear_ shadows and _clean_
high lights as possible, with not too high a relief. When the print is
completely finished, it should be placed in a 2 per cent cold solution
of ammonia, this allowed to act for two minutes and then rinsed for one
minute in clean water. Then the print, which is considerably swollen,
should be very carefully dried off, so that no ink comes off on the
cloth, and the latter leaves no imprint of its structure. Now the whole
print is gone over with a clean brush, on which is a _very little pure
oil color_. By thus using light, transparent (_lasur_) colors, and
only such ought to be used for this purpose, the print may be given an
extremely delicate film of ink, through which the first image shines with
full vigor. This gives an effect similar to that which the gum printer
obtains by multiple printing.
According to whether the whole or only parts of the print are gone over
with the “lasur” color, the most varied effects are obtained, such as
deepening of the shadows, or lowering of the high lights, or both.
It is naturally impossible to describe this process exactly in print.
Much must be left to artistic feeling, without which hair-raising color
discords will probably be produced. Still, in order to give the beginner
some starting point, it may be mentioned that black, brown or red tones
may be easily treated with inks shaded towards grey, blue with pure grey,
and so on.
The following summary of color mixtures for the beginner is also given:
_red-brown_ is obtained by mixing bone black, Indian red, and possibly
dark alizarin lake; _violet_ results from bone black with red and blue;
_dark green_, from black, cadmium and blue; _brownish-green_, from black
and indigo; _bright green_, from a little black with cadmium and indigo;
_red chalk_, from black, brown and Indian red.
The individual tints will obviously vary considerably, according as more
or less of any given color is taken. This is entirely a matter of taste
and must be left to the judgment of the individual.
When the stiff ink is ready on the glass plate, it is advisable to
carry out all further manipulations on a white porcelain palette or
tile, because the mixtures can be much more easily judged in tone and
consistency on these white supports. The mixtures are best made with the
stiff spatula (putty knife).
PERMANENCY.—The permanency of home-made inks prepared by oneself is
satisfactory if they are preserved from dust and air. My inks have kept
for periods exceeding three months, with the most satisfactory results.
[Illustration: FIG. 4]
INK-GRINDING MACHINES.—For all ordinary purposes the inks prepared in
the manner just described are perfectly satisfactory. For inks, however,
which must be extremely fine this method of mixing is not sufficient,
therefore, I had a small machine constructed (Fig. 4), which consists
of two rollers turning in opposite directions. The hand-ground inks are
placed on these rollers and kneaded with strong pressure for two or three
minutes. The whole machine is 25 cm high and 20 cm wide (10 × 8 in.), and
can be conveniently fastened on the corner of any table. The resultant
inks are of a fineness and quality which have not been bettered by large
manufacturers.
ADDITIONS TO THE INKS.—If it is desired that the inks should dry matt
on the bromoil print, so that the defatting with benzol may be omitted,
then one should add to the home-made inks a small quantity of one of the
following mixtures:
(a) Beeswax 1 g (15 gr.); melt by heat and add with stirring 20 drops of
linseed oil. As it cools a salve-like mass is formed. Or:
(b) 1 g (15 gr.) kieselguhr (infusorial earth) rubbed up with linseed oil
to a quite thin fluid paste.
It should be noted that these mixtures, in consequence of their content
of linseed oil, make the inks softer.
Books on Photography
Optics for Photographers, by Hans Harting, Ph.D. Translated by Frank R.
Fraprie, S.M., F.R.P.S. 232 pages. Cloth, $2.50.
Chemistry for Photographers, by William R. Flint. 2nd edition. 218 pages.
Cloth, $2.50.
Pictorial Composition in Photography, by Arthur Hammond. 234 pages, 49
illustrations. Cloth, $3.50.
Photo-Engraving Primer, by Stephen H. Horgan. 81 pages. Cloth, $1.50.
Cash from Your Camera. Edited by Frank R. Fraprie, S.M., F.R.P.S. 87
pages. Paper, $1.00.
Pictorial Landscape Photography, by the Photo Pictorialists of Buffalo.
252 pages, 55 illustrations. Cloth, $3.50.
Photographic Amusements, by Walter E. Woodbury. 9th edition. 128 pages,
100 illustrations. Cloth, $1.50.
Practical Color Photography, by E. J. Wall, F.C.S., F.R.P.S. 248 pages.
Cloth, $3.00.
Bromoil Printing and Bromoil Transfer, by Dr. Emil Mayer. Translated by
Frank R. Fraprie, S.M., F.R.P.S. 199 pages. Cloth, $2.50.
PRACTICAL PHOTOGRAPHY SERIES
Edited by Frank R. Fraprie, S.M., F.R.P.S.
Editor of _American Photography_
1. The Secret of Exposure.
2. Beginners’ Troubles.
3. How to Choose and Use a Lens.
4. How to Make Prints in Color.
5. How to Make Enlargements.
6. How to Make Portraits.
7. How to Make Lantern Slides.
8. The Elements of Photography.
9. Practical Retouching.
10. Practical Printing Processes.
11. Modern Development.
_Each volume sold separately._ Cloth, $1.00; paper, 50 cents.
American Photography Exposure Tables, 101st thousand. Cloth, 35 cents.
Thermo Development Chart. 25 cents.
_American Photography_, a monthly magazine, representing all that its
name implies. 25 cents a copy. $2.50 a year.
PUBLISHED BY
American Photographic Publishing Co.
428 Newbury St., Boston 17, Massachusetts