Method of preparing photographic emulsions

Claim 1

IN A METHOD OF PREPARING WASHED SILVER HALIDE DISPERSIONS, THE STEPS WHICH COMPRISES MIXING TOGETHER A WATER-SOLUBLE SILVER SALT AND A WATER-SOLUBLE HALIDE SALT IN AN AQUEOUS SOLUTION OF A GELATIN DERIVATIVE WHOSE PRESENCE RENDERS THE DISPERSION COAGUABLE AT A PH WITHIN THE RANGE OF PH 3-4.5, WHICH 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 IN GELATIN DERIVATIVE THUS FORMED BY ADJUSTING TO SAID PH. WHEREBY SILVER HALIDE-GELATIN DERIVATIVE GRAINS ARE FORMED, AND SUBSEQUENTLY SEPARATING THE SILVER HALIDE-GELATIN DERIVATIVE GRAINS THUS FORMED FROM THE LIQUID PORTION OF THE MASS.