METHOD OF MANUFACTURING SILVER BROMIDE/IODIDE PHOTOGRAPHIC EMULSIONS Russian patent published in 1997 - IPC

FIELD: photographic industry. SUBSTANCE: silver bromide/iodide photographic emulsions are manufactured using controlled two-jet emulsifying by introducing into ammonia-containing water-gelatin solution aqueous silver nitrate solution and KBr/KI-containing aqueous solution, after which solid phase is precipitated and subjected to two-fold dispersing in water-gelatin solution and then to chemical and spectral sensitizing. According to invention, the two solutions are introduced simultaneously with constant rate at constant pBr value (3.5-4.0) for period of time constituting 20-80% of total emulsifying time. Then pBr value is reduced to 3-3.2 and kept constant until simultaneous introduction of solutions is terminated. EFFECT: improved manufacturing procedure. 1 tbl