PROCESS OF PREPARATION OF HALOGEN-COPPER PHOTOGRAPHIC EMULSION Russian patent published in 1997 - IPC

FIELD: technology of non-silver photographic materials, production of photographic emulsions of basis of copper halogenides. SUBSTANCE: aqueous-gelatine solution No.1 including ammonium bromide as halogen-carrying compound and hydroxylamine or hydrazine as reducer of bivalent copper is injected with solution No.2 containing sulfate of bivalent copper or nitrate of bivalent copper and aqueous solution of ammonia. Reaction mixture is acidified and precipitation of solid phase at pH about 4.0 is conducted which later is dispersed in aqueous-gelatine solution. EFFECT: increased photographic characteristics (high contrast range, low for, fine grain effect), diminished cost of process of preparation of halogen-copper photographic emulsion. 3 cl, 3 tbl