Negative Process

a chemical process that converts the latent image, which was created in the photosensitive emulsion of still or motion-picture film upon exposure, into a visible image, called a negative.

In the negative process the exposed photosensitive material is developed—that is, the exposed microcrystals of silver halide, which form the negative image, are selectively reconstituted as grains of metallic silver. In color film, an image composed of pigments is formed on the basis of an image consisting of metallic silver. The negative process includes photographic fixation (conversion of the remaining silver halides into soluble salts), washing (removal by water of soluble materials), and drying (removal of water from the film). If the negative image must be corrected, the film undergoes photographic intensification or reduction.

In the treatment of materials for color photography, the reconstituted silver must be removed. For this purpose the film is bleached: the metallic silver is oxidized to water-soluble compounds. It is also hardened, to increase the strength of the photo-sensitive emulsion. The operations in the negative process may be done manually or by special machines.