Bichromate, also known as potassium bichromate or potassium dichromate, is a chemical used in photographic processes for bleaching and as a sensitizer for gelatin emulsions. It plays a key role in alternative photographic printing techniques, such as gum bichromate printing, where it helps control tonal range, contrast, and image permanence. Photographers using traditional or experimental darkroom methods rely on bichromate to create unique textures and artistic effects in their prints.