Bromoil Printing

By Ralph A. Davis What is a Bromoil Print? A bromoil is a print in which the original silver image has been replaced with one consisting of an oil pigment. This offers the worker controls provided by no other printing medium... In addition, the freshly pigmented image can be transferred to drawing paper, making a bromoil transfer. Through this transfer technique the bromoilist has available for use many of the beautiful artists' papers, with their rich and distinctive surfaces. The Process A photographic paper having a soft, unhardened emulsion is required. Only a few modern papers will be found suitable for use. (Still true, after over 30 years! - Ed.) After exposure and processing, the print is placed in a tanning bleach, which hardens the gelatin where the image has been, in direct proportion to the amount of exposed silver in the image... When the pigmenting is to be done, the dried, bleached print (now called the matrix) is placed in a tray of water, during which the gelatin will swell and absorb water in inverse proportion to the amount of hardening... The bromoil ink is applied to the moist print with a flat "stag foot" brush. The ink consists essentially of an oil base (usually linseed oil) and a pigment... Materials Required You will need something on which to place the matrix when it is ready to be inked. (The author here explains how to cover a drawing board with oilcloth; today we would use either a melamine - "Formica"- board, or cover the board with adhesive-backed plastic. - Ed.) A piece of chamois at least 10 x 13 inches will be needed, and a large, finegrained plastic sponge. Buy a putty knife with a flexible blade, and a couple of 6x6 inch ceramic tiles or plastic squares for preparing the ink. Other essential articles are an artist's kneadable eraser and a large amount of absorbent cotton. For cleaning brushes after use, have on hand a suitable brush cleaner. Obtaining bromoil brushes may present some difficulty... You will need a brush at least one inch or larger in diameter. A second small brush (1/4 inch) will also be found useful. For those trying the process for the first time, an inexpensive but serviceable brush can be adapted from a good, fine-bristled sash brush used by house painters... However, as bromoil brushes are used for stippling and need a flat inking surface, it will be necessary to cut about 1/2 to 3/4 inch off the bristles of the sash brush in a slanted cut, using a large, sharp pair of shears. This should result in a flat surface that can take up and deposit the ink on the print... One of the greatest factors in success or failure in bromoil is the ink... I recommend the use of homemade ink, made from linseed oil and pigment. When you have mastered the facility of making it, you will find it superior to anything you can buy. Processing Procedures To make a good bromoil, the original print must be made exactly right or failure will result when it is later inked. The print should be made considerably darker than one would ordinarily make it for viewing. The highlights should have a considerable deposit of silver, while at the same time the deepest shadows should not have blacks quite as deep as the paper is capable of producing. This is why a soft negative is essential in producing this contraction of the tonal scale. A correctly made print, held up to a 60 watt bulb, should show full highlight details with open shadows in full detail. Old-time bromoilists recommended Amidol as a non-hardening developer, but Dektol will be found satisfactory diluted 1:2 (some workers prefer 1:3 or even 1:4). When development is complete, the print is given a plain water rinse, and then fixed in a solution of plain hypo crystals and water, nothing else. No hardener of any kind should be used for prints intended for bromoil - just two ounces (60 grams) of hypo crystals per quart (liter) of water. Use fresh fixing solution each time as it does not keep. After fixing, the prints are given the usual washing and dried without application of heat. The bleach bath is made up as follows: to 12.5 ounces (354 ml) of water, add 20 drops (1 ml) of concentrated sulfuric acid. Then dissolve in order, 1 ounce (28 grams) of copper sulfate, 1 ounce (28 grams) of potassium bromide, and 25 grains (1.62 grams) potassium bichromate. This is a stock solution. For use, dilute one part with four parts of water. (The procedure for bleaching, washing, refixing, washing, and drying are explained in the article, and not extracted here. -Ed.) Preparing the Ink The materials needed include - besides the putty knife and 6x6 tiles - a small bottle of Sunbodied or Thickened Linseed Oil (which has the color and consistency of honey), a small bottle of Refined Linseed Oil (a thin water-white oil), and about 4 ounces of a dry pigment such as Ivory Black, a warm black. All these items may be obtained in an artists supply store. Also buy a few wooden skewers (sticks) about 4 or 5 inches long, used by doctors for swabs. When you are ready to make the ink, sit facing your source of light. As the consistency of the ink must be judged by its matte or glossy appearance, backlighting will be found to be a great help. Dip a skewer about an inch into the thick linseed oil and keep turning the skewer so as not to drip. Deposit the oil on the tile by rolling the skewer sideways on the tile. Then take up some pigment, using the tip of a penknife, and drop it into the oil. Work the pigment into the oil by alternately stroking it a few times with the putty knife and then rolling it upon the knife and respreading it. Continue until the pigment is fully absorbed by the oil... Soft pastel crayons may be used as a source of pigment. The crayon should be broken up, pulverized and then finely ground, using a glass pudding dish and the back of a spoon... The most useful colors are ultramarine blue, burnt umber, thalos blue, and deep permanent green. Always use the deepest shade you can get in the color. It is also advisable to add a small amount of black when using these colors to give sufficient depth of tone. Use ivory black with the warm colors, and lamp black with the cool colors. At first the mixture will be soft and glossy. Keep adding small amounts of pigment and mix as above. You will find that the ink, after a time, will begin to lose its thin glossy consistency and require some effort in handling. Continue until you find that the ink, when stroked with the putty knife, remains matte in appearance for about one second before turning glossy. At this point add one drop of the thin linseed oil and work it into the ink. There should now be a lag of about 1/2 second between the matte and glossy appearance when stroked with the putty knife, at which time it is ready for use. If you do not wish to use the ink immediately, it may be preserved by rolling it up on the putty knife and placing it on a small (about 3 inches) square of aluminum foil, folding the foil over the ink several times to protect it from the air... Inking When you are ready to ink the bromoil print, fill a tray with water at 85F... Immerse the bleached print (now called the matrix) face up in the water, and in a minute or two when it has flattened out, turn it upside down in the water, making sure no air bubbles cling to the underside... If the temperature is too high, the matrix will be overswollen; if too low, it will be insufficiently swelled. After the matrix has been soaking for about 20 minutes, it should be ready to ink. When the soaking time is about completed, soak the chamois and the plastic sponge for a minute or so, and then squeeze out all the excess water. Both of these should always be damp when used. Now take the matrix and lift it from the water by one corner, letting it drain for a few seconds. Using the damp sponge, stroke the back a few times to remove the excess water. Then place the matrix face up on a dry blotter and gently pat the face of the matrix. This is important; any drops of water remaining on the back will seep through the base of the paper during the inking and cause white spots to appear. The matrix should then be placed face up on the plastic-surfaced board. Take the damp chamois and fold it so that it forms a convenient pad. Note that the chamois should be used damp; never use a dry chamois on a matrix. Gently pat the face of the matrix with the chamois until all of the water on the surface has been removed. Be sure to also check for any drops of water on the board along the edges of the matrix. Should the brush pickup a single drop of water during the inking, a series of white spots will result. Now take up the bromoil brush and press it once firmly in the bromoil ink. On a clean spot on the tile, stipple about 50 times on the tile. This stippling motion is not a brushing motion but an up and down movement which is used in stenciling or when a woman pats powder on her face. Remember, if you have too much ink on the brush when you start to ink, you will find yourself in difficulty. However, if you find that when you stipple out the ink on the tile that it refuses to come off the brush easily, it is an indication that the consistency of the ink is too hard (stiff) and another drop of light oil should be added. Start applying the ink with an up and down stippling motion, starting perhaps in a corner of the matrix. Be sure you use the full flatface of the brush in applying the ink. It is best to work in small overlapping circles to insure even inking... Keep applying the ink until the proper depth of tone is obtained.

Information provided by: http://www.psa-photo.org/bromoil.htm