Process for preparing yellow colloidal silver

Claim 1

A PROCESS FOR PREPARING YELLOW COLLOIDAL SILVER WHICH TRANSMITS LIGHT OF WAVELENGTH OVER 500 MU AND HAS AN ABSORPTION MAXIMUM IN THE REGION FROM 400 TO 450 MU WHICH COMPRISES ADDING TO AN AQUEOUS SOLUTION CONTAINING 2% TO 20% BY WEIGHT OF A WATERPERMEABLE COLLOID HAVING PROTECTIVE COLLOID PROPERTIES AND A SOLUBLE SILVER SALT, AN AQUEOUS SOLUTION CONTAINING 2% TO 20% BY WEIGHT OF A WATER-PERMEABLE COLLOID HAVING PROTECTIVE COLLOID PROPERTIES AND A SOLUBLE INORGANIC BROMIDE BETWEEN 1% AND 20% BY WEIGHT IN EXCESS OF THE SILVER SALT WHICH IS PRESENT IN AN AMOUNT TO FORM A CONCENTRATION OF SILVER BROMIDE IN SAID COLLOID OF 0.1% TO 2% BY WEIGHT ADMIXING SUFFICIENT DILUTE ALKALI SOLUTION TO THE RESULTING SOL TO RAISE THE PH TO AT LEAST 8.5 AND AN AQUEOUS SOLUTION CONTAINING IN A STOICHIOMETRIC EXCESS A NITROGEN-CONTAINING PHOTOGRAPHIC DEVELOPING AGENT HAVING A REDUCTION POTENTIAL OF AT LEAST 0.3, HEATING THE ADMIXTURE TO 100*F. TO 200*F. FOR A PERIOD OF AT LEAST 10 MINUTES, COAGULATING THE COLLOID DISPERSION, AND WASHING THE SOLUBLE SALTS FROM THE COAGULATE.