Last Revision: 14 September 2005
Some Preliminary Notes on Bromoil
There is nothing new here, but I am offering these notes for the beginner.
I hope to write a complete article on bromoil at some time in the future when I have gained significant experience, but until then these preliminary notes will have to suffice.
There are so many variables in the bromoil process, that it is almost impossible for any two bromoilists to follow exactly the same procedure. However, there are recommended starting points that have not changed much in the century since the process was invented. The two primary variables are the amount of swelling of the gelatine matrix and the relative consistency of the ink used; others include water quality, exposure time, paper used, type of developer, development time, bleach formulation, inking method, etc.
1. Paper. Virtually any silver gelatin paper could be utilized in the early days of bromoil, but in the 1920’s manufacturers began to superharden the gelatin in their papers as well as make papers with very smooth, glossy surfaces. Bromoilists found such papers more difficult to ink, so many manufacturers made special bromoil papers with non-superhardened emulsions and matte surfaces. By the mid 1930’s some bromoilists had discovered methods that enabled them to utilize supercoated papers for the process, and by the late 1950’s many special bromoil papers were discontinued due to declining sales.
Today there are a few small manufacturers that produce papers especially intended for the bromoil process, including Kentmere, J&C Photographic, and David Lewis. In addition, almost any paper with a semi-matte or matte surface can be utilized. I have gotten excellent results with Luminos Charcoal R, J&C Bromoprint, Bergger Brom 240, David Lewis paper, Agfa Multicontrast Classic, Forte Elegance Polywarmtone, and several other papers.
2. Exposure. To start with, find the exposure that gives full detail in the most significant area of the print. The general rule of thumb is to double that exposure to make a print suitable for bromoil. With some non-superhardened papers the exposure increase may be only 50%, but could run as high as 300% if you wish to reproduce fine high value detail--such as in a high key image or a nude. For most superhardened papers, doubling the exposure is required. Pretend you have a “dark” aesthetic and prefer all your prints to be dark and moody--make a nice, dark print, then double that exposure to make the bromoil matrix, and you will almost certainly be close. With experience, you will be able to tell when a print is dark enough--or too dark. This can vary from paper to paper.
With variable contrast papers, Gene Laughter recommends using one contrast grade lower than normal for most prints. This is not usually necessary with pyro negatives, because the yellow stain acts as a contrast reduction
filter--in fact, sometimes I have to use one to two grades higher than normal contrast for pyro negatives.
Many old bromoilists state that you can use any developer but their favorite is an amidol formula--of which there are many. Amidol was (and still is) favored by many because it causes no staining or tanning of the gelatin. I recently developed one print in Dektol (1:8) and another in an amidol formula, using the exact same exposure and development times. These two prints inked identically--I could tell no difference between them.
If you wish to use an amidol formula, I can recommend the one given by David Lewis, which is quite old.
I tried using factorial development, as recommended in some old manuals, but ultimately I found that a development time of about three minutes seems to be optimal with Dektol (1:8); this also happens to be the time recommended by Gene Laughter and David Lewis. For R77M , Ansco 120, Dektol (1:10), or Amidol, I use 4 minutes.
With Dektol (1:8) and graded papers I sometimes find it useful to use water bath development: I agitate continuously and allow the blacks in the image to emerge fully, which usually takes 30 to 50 seconds, then I remove the print to a tray of plain water where I let it sit with no agitation for 30 seconds. Then I alternate 10 seconds of agitation in the developer with 30 seconds sitting still in the water bath until 3 to 5 minutes have elapsed. If you don't allow the blacks to emerge fully at the beginning of development, they may ink unevenly.
4. Stop Bath. Development should be stopped either with a plain water stop or a diluted acetic acid stop. I use 3/4 ounce of 28% acetic acid in one quart of water (or about 22.5 ml in one liter), which is half the amount of acetic acid I use for normal silver printing. The time in the stop bath is 30 seconds, with continuous agitation. I then rinse both sides of the print under running water before continuing to the fix--this keeps the plain hypo from becoming too acidic.
5. Fixing. Fix each print for 5 minutes, with continuous agitation, in a 10% solution of plain hypo (sodium thiosulfate). Some practitioners use an acidified sodium thiosulfate fixing bath (such as Kodak fixer) at this stage, but most say they prefer to use plain hypo. Gene Laughter says he finds that a print fixed in acidified fixer doesn't ink as easily. The cheapest source I have found for plain hypo is Artcraft Chemicals.
6. Drying and Superdrying. Prints should be air dryed for six hours. (There are quick methods that recommend drying with heat, but most bromoilists over the years have recommended air drying for the beginner at bromoil. The quick method is for expert bromoilists.) After the prints have dried slowly in the air, they can then be superdried. If you have a dry mount press, preheat it to 250° and press the print between two matte boards for 2 or 3 minutes. You can also move the print over a gas stove burner on medium heat for 20 to 30 seconds. This drives all remnants of moisture out of the print and leaves it bone dry--it is also said to soften the gelatin and make it take ink more easily. Superdrying is done again to the matrix just before it is soaked for inking.
7. Bleaching & Tanning. Mix three solutions as follows:
Solution A. 100 grams copper sulfate in 1 liter of distilled water (10% solution).
Solution B. 100 grams potassium bromide in 1 liter of distilled water (10% solution)
Solution C. 10 grams potassium bichromate in 1 liter of distilled water (1% solution) (All these solutions keep indefinitely in brown glass bottles.)
Take 70ml A, 70ml B and 30ml C, and add distilled water to make 1 liter of working solution--this will bleach & tan ten 8x10 prints. Today this is the most widely-used bleach formula, though there are a number of variations.
The optimum time with this bleach is 8 minutes, but don't be afraid to continue to 10 or even 15 minutes if necessary.
The copper sulfate solution is the bleaching agent, while the dichromate solution is the tanning agent (which hardens the gelatin). It is possible to separate the bleaching and tanning processes, though in general I find that a properly exposed and developed print will bleach in less time than it takes to tan, and so it is a waste of time to separate them. But separating the solutions can be educational and is probably worth doing at least once. Simply mix one solution with 70ml A and 70ml B in a liter of water, and another with 70ml B and 30ml C in a liter of water. When I did this, I learned to tell the difference between a matrix that has not been bleached enough and a matrix that has not been tanned enough. The optimal bleach time seems to be about 6 or 7 minutes, but some prints require 10 minutes or more to tan fully.
Mix the used bleach solution with used fix or used hypo clearing agent before pouring down the drain.
8. Acid Bath. The fixed matrix has a slight grey-green color, caused by residual chrome oxide.
This can be removed by a 2 minute bath in 1% sulfuric acid. Many modern workers omit this step. More than one writer on bromoil has stated that the acid bath allows the matrix to accept ink more
easily--however, I can’t tell much difference. I have noticed that sometimes the grey-green color shows through in delicate highlights, such as are often seen in nudes, so I sometimes use an acid bath for such prints.