Gelatin

Glossary Terms

Gelatin (or gelatine) is a proteinaceous material derived from the collagen in animal skins and bones. It is used as the flexible medium in which grains of light-sensitive substance are dispersed in virtually all photographic film and plates made since the early 20th century. Gelatin serves its purpose well, because it swells rapidly when exposed to chemical solutions, so each chemical gains access to the emulsion quickly, and is quickly washed out afterward. At the end of processing, the gelatin can be hardened (usually with acetic acid) making the film more robust. As a by-product of the meat industry, gelatin is plentiful and cheap, so there has been no significant effort to replace it.