Definitions for "Gum Bichromate"
Contact printing process once very popular for the manipulative, impressionistic effects it makes possible. Drawing paper is coated with a mixture of gum, potassium bichromate and a pigment of any chosen color. This is then exposed to light behind a negative. Also known as the photo aquatint process.
During the Pictorialist period many photographers used this process, alone or in combination with other processes. Gum prints can be identified by a softness and graininess and somewhat resemble lithographs. This process has been used to make full color prints, but accurate registration (the alignment of one pigment printed over another0 is difficult to achieve. The process is especially suitable for obtaining painterly effects. Gum printing is being revived by some contemporary photographers.
An early color process in which the image is formed of pigmented gum arabic; popular with pictorialist photographers, particularly Frenchman Robert de Machy.