A Simplified Method of Preparation of Di-Ammine-Silver Hydroxide for Reticulum Impregnation; Comments on the Nature of the So-Called Sensitization Before Impregnation

Abstract

A satisfactory di-ammine-silver hydroxide soln. may be repeatedly and con-sistently prepared by adding 9 or 10 volumes of 10% AgNO3 soln. to 1 vol. of 28% ammonia water, running in the first 6 or 7 vols. rapidly and proceeding cautiously from then on, shaking until clear after each addition, until a faint permanent turbidity is reached. The essential nature of Gomori''s iron alum treatment and of Wilder''s uranyl nitrate step following the Weigert permanganate-oxalic-acid sequence appears to be an oxidation, since the same results may be achieved with chromic acid, H2O2, Na iodate and elemental iodine, and since this step is better omitted on previously chromated material.