FORMULARY GUM BICHROMATE KITS are one of the most versatile and least complicated of the non-silver processes. We now offer two Gum Printing kits: the Classical containing only black pigment, and the Contemporary, containing red, blue, and yellow pigment. Both kits have liquid Gum Arabic, Ammonium Dichromate, and extensive directions for their use. Gum Printing is unique among all the printing processes. It is distinguished by unlimited flexibility. The printer has complete control and may produce prints of any color or contrast. These prints are characterized by a long, open scale that is soft and romantic, but fine detail is not possible.
Gum Printing uses water color pigments rather than metal to form the base. The paper is coated with the gum arabic and a dichromate salt. When dried paper is contact printed, the exposed areas become water insoluble. A warm water development dissolves the gum from the unexposed areas. The pigment in the retained areas forms the image. Multiple printing with different colors is a common technique.
The difference between the Classical and the Contemporary kits is the Classical will only do black and white while the Contemporary contains 3 color pigments.