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

FIELD: chemical photographic industry. SUBSTANCE: silver bromide/iodide photographic emulsions are prepared by way of controlled two-jet emulsification using simultaneous introduction into ammonia-containing water-gelatin solution of silver nitrate aqueous solution and aqueous solution containing potassium bromide and iodide at constant pBr value - 2.9-3.5 followed by separation of solid phase, washing, and dispersing of obtained precipitate in water-gelatin solution. Resultant emulsion is further chemically sensitized at pBr 2.5-3.5 and pH 6-7 by introducing sodium thiosulfate and sodium benzenesulfinate, incubating emulsion for 40- 90 min, adding gold thiocyanate and then, 1-30 min later, methyl p- toluenesulfonate-2-methylbenzthiazol in quality increasing with time, whereupon emulsion is incubated for 50-100 min and is subjected to spectral sensitizing. EFFECT: improved procedure. 1 dwg, 2 tbl