Gum Bichromate Process

Gum bichromate is a photographic printing process that was introduced in 1894. It can be repeated on the same sheet of paper for a multichromatic result. Traditionally it is a contact method, though any method which selectively emits ultraviolet light can be used. The process coats plain paper with a photo reactive chemical mixture, exposes an image, then goes through a simple development stage.