METHOD OF PREPARING IODO-BROMO-SILVER PHOTOGRAPHIC EMULSION Russian patent published in 1997 - IPC

FIELD: photomaterials and reagents. SUBSTANCE: method of preparing ammoniacal iodo-bromo-silver photographic emulsion at AgJ content 1-5 mole % involves mixing ammonium halides and/or alkaline metal and silver nitrate solutions in an aqueous gelatin and stabilizing agent solution, physical maturation, solid phase separation, dispersing in gelatin solution and chemical maturation. The first solution of silver nitrate is ammoniated and contains alkaline metal iodide at amount 0.002-0.04% of silver nitrate mass. Silver nitrate and alkaline metal iodide were dissolved together at 30-40 C in ammonia aqueous solution up to the complete ammoniation or ammonium nitrate solution at 30-40 C is added after dissolving in ammonia aqueous solution up to the complete ammoniation and water is added up to the required volume. Mixing parent solutions of ammonium halides and/or alkaline metal and silver nitrate is carried out by mono- or dijet method. One or some silver nitrate solutions can be used being alkaline metal iodide has the first ammoniated silver nitrate solution. EFFECT: improved method of emulsion preparing. 1 tbl