Photographs in which the tones or colors are reversed from their appearance in nature, usually on a transparent support of celluloid, acetate, or on paper, intended for the purpose of producing positive prints. For finished prints in which tones or colors are reversed, see "negative prints." When a glass plate is painted or drawn on and a photographic print made from it, use "clichés-verre."

Source: Art & Architecture Thesaurus

http://vocab.getty.edu/page/aat/300127173