METHOD OF MANUFACTURING PHOTOGRAPHIC SILVER BROMID-IODIDE EMULSIONS Russian patent published in 1995 - IPC

FIELD: chemical-photographic industry. SUBSTANCE: method of synthesis of silver bromid-iodide photographic emulsions involves the steps of: fractional single-jet emulsification, physical ripening, separating solid phase, dispersing, chemical and spectral sensitization. Emulsification is carried out at reduced ratio of gelatin mass to metallic silver mass and at increased value of pBr in the first stage up to ρ = 0,26-0,45 equal to 0.26-0.45 and pBr equal to 0.19-0.3, up to ρ = 0,16-0,28 equal to 0.16-0.28 and pBr equal to 0.55-0.65 in the second stage, up to ρ = 0,13-0,22 equal to 0.13-0.22 and pBr equal to 0.8-1.3 in the third stage with time intervals between the stages equal to 4-8 min, dispersing being carried out up to ρ = 0,8-1,2 . equal to 0.8-1.2. EFFECT: reduced fog density, prolonged high properties of emulsions. 2 tbl