The gum process was introduced in 1894, and was one of several introduced about this period, enabling photographers to obliterate many of the photographic qualities. A gum bichromate practitioner could alter the tones, get rid of details, and using a brush, pencil or rubber, could change an image so much that it looked more like a painting than a photograph.
The paper would be coated with gum arabic mixed with a sensitive chemical, which would harden on exposure to light. The exposed gum layer containing a pigment was then washed with water, leaving the hardened parts behind. The print could then be treated with brushes and thus be modified considerably. Gum bichromate prints have little detail, but may sometimes appear almost like charcoal drawings.
Stieglitz, writing about the process, said that in it "the artist has a medium that permits the production of any effect desired. These effects are so "unphotographic" in the popular sense of that word as to be described as illegitimate by those ignorant of the method of producing them. In this process the photographer prepares his own paper, using any kind of surface most suited to the result wanted, from the even-surfaced plate paper to rough drawing parchment; he is also at liberty to select the color in which he wishes to finish his picture, and can produce at will in india-ink, red-chalk or any other color desired. The print having been made he moistens it, and with a spray of water or brush can thin-out, shade, or remove any portion of its surface. Besides this, by a system of re-coating, printing-over, etc., he can combine almost any tone color- effect."
One of the leading exponents of this process was Robert Demachy. It was eventually superseded by the bromoil one.
© Robert Leggat, 1999.