About Gum Printing

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About Gum Printing—By: Julia Zanes

Hope discovered gum printing in 1988, when I was in art school. She’d asked me to take a class in alternative photo processes because she wanted to learn platinum printing. Platinum printing is, of course, an expensive, precious technique. Gum printing is affordable, as colorful as the pigments you choose, and the printing can be done outdoors. It is, in many ways, perfectly suited to Hope’s personality, and she mastered it. Gum printing was patented in 1855. Because it involves contact printing, which means the negative sits directly on the printing paper for exposure, the final print and the negative from which the photograph is made are the same size. So Hope’s version of the process began in the darkroom, where she enlarged her negatives. She generally used 120mm film in Diana cameras, so those 120mm negatives would be enlarged to sizes ranging from 8”x10” to as large as  22” x 30”. Put simply, she was using her enlarger to make a negative into a bigger negative. She did that onto “direct positive sheet film,” but she did it as negatives rather than positives. That part of the process got her to a negative large enough to make contact prints. The printing process itself was done outside, in the sun. She exposed the negative onto pre-prepared paper, then developed it in water. It sounds almost wholesome, but the pre-preparation of the paper was more complicated. Hope started with a traditional etching paper, Rives BFK, which she coated with gelatin and formaldehyde. Following that, she brushed the paper with a mixture of gum arabic, pigment, and potassium dichromate (a light sensitive chemical). Formaldehyde is, of course, described as a “highly toxic systemic poison.” She probably showed just enough caution but not more. For Hope, the process became a seasonal one; in the winter she enlarged the negatives in the darkroom, using that direct positive sheet film to get that larger negative. In the summer, she printed from those negatives. Once safely past the exposure to formaldehyde and dichromate, the process is very pure and beautiful: again, she exposed the negatives in the sun and developed them in water, all of which can be done outdoors. Hope had trays of water set up all over her field, working on many prints simultaneously, as the weather allowed.  She perfected a gum printing technique and even developed her own method of registering the negatives, allowing for up to four layers of pigment. The uniqueness of Hope’s prints comes in part from the fact that many of her original negatives were made using her Diana cameras, which come with plastic lenses, each one a little different from the others. Hope made the majority of her gum prints, a few of which you see here, between 1988 and 2004.