About Gum Bichromate

These landscapes are produced using the 19th century Gum Bichromate and Cyanotype printing processes. “Non-Silver” processes gain their name from the fact that they do not contain the traditionally standard light sensitive ingredient, silver. These processes were developed in the mid-1800s as an archival, permanent alternative to the (then) impermanence of silver-based photography.

Each of my prints begin as a sheet of Fabriano 140 lb. rough watercolor paper, coated by hand with a layer of Cyanotype photo emulsion. This light sensitized paper is then contact printed with a full size negative and exposed in direct sunlight for 10 minutes. After development in water, an image is produced in rich Prussian blue tones. The print is then hand coated again with a layer of Gum Bichromate solution (containing green gouache pigment) and contact printed in full sunlight for 8 minutes. After water development, this second exposure rests in register on top of the blue image and the print begins to take on natural tones of greens and blues. After this layer has dried, a third exposure is made in brown pigment and developed to reveal a landscape now containing warm, natural tones of wood. A final exposure is made in black, to deepen just the shadows of the scene. In all, four exposures are made over several days (of sunshine!) in careful registration on top of one another to produce these handmade prints. The resulting artwork is archival, comprised of very permanent, “AA” lightfast rated Winsor Newton gouache pigment printed on acid free watercolor paper.

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