Without chemistry, photography, as it is known, would not exist. Photography is a complex array of chemical reactions. Each step, from the manufacture of the film through the final prints or slides being viewed, has its own particular chemical processes.

The film that is used in most cameras is a thin base of gelatin (peptides of collagen) which is bonded to a polymeric plastic sheet cut into strips. The gelatin is hardened during manufacture by cross-linkage of the polypeptides. This is so the gelatin matrix is not damaged by mechanical movement through the camera. The gelatin acts as a support for the light-sensitive material that is used to capture an image. The gelatin protects the light sensitive material and it also enhances its sensitivity. The light-sensitive material used is a silver halide. With modern camera film silver bromide generally is used. Other photographic emulsions...