Method of preparing photographic emulsions

Claim 1

IN A METHOD OF PREPARING WASHED SILVER HALIDE DISPERSIONS, THE STEPS WHICH COMPRISE MIXING A WATER-SOLUBLE SILVER SALT AND A WATER-SOLUBLE HALIDE SALT IN AN AQUEOUS SOLUTION OF A PEPTIZING COLLOID, MIXING THEREWITH AT LEAST 2 PARTS OF A GELATIN DERIVATIVE PER PART OF THE PEPTIZING COLLOID, THEREBY RENDERING THE SILVER HALIDE DISPERSION COAGULABLE AT A PH WITHIN THE RANGE OF PH 3-4.5, WHICH GELATIN DERIVATIVE IS SELECTED FROM THE GROUP CONSISTING OF THE AROMATIC SULFONYL CHLORIDE DERIVATIVES OF GELATIN, THE CARBOXYLIC ACID CHLORIDE DERIVATIVES OF GELATIN, THE CARBOXYLIC ACID ANHYDRIDE DERIVATIVES OF GELATIN THE AROMATIC ISOCYANATE DERIVATIVES OF GELATIN AND THE 1,4 DIKETONE DERIVATIVES OF GELATIN, COAGULATING THE DISPERSION OF SILVER HALIDE BY ADJUSTING TO SAID PH WHEREBY SILVER HALIDE-PEPTIZER-GELATIN DERIVATIVE GRAINS ARE FORMED AND SUBSEQUENTLY SEPARATING THOSE GRAINS FROM THE LIQUID PORTION OF THE MASS.