Improvements in sensitive photographic materials

摘要

650,656. Photographic silver halide emulsions. KODAK, Ltd. Dec. 20, 1948, No. 32865. Convention date, Dec. 19, 1947. [Class 98 (ii)] A photographic silver halide developing out emulsion contains a ruthenium halide RuX 3 , wherein X,represents a halogen atom. The ruthenium halide may also be incorporated in a colloid layer above or below the emulsion layer, and may be the chloride, bromide, or iodide. The ruthenium halide may be incorporated in a concentration of from 260 to 3900 mgs. per kilogram of silver nitrate equivalent of the silver halide, and is preferably incorporated after the final digestion of the emulsion, but may be incorporated during or before final digestion. The ruthenium halide maintains the sensitivity and fog level of the emulsion at or close to initial optimum values under tropical storage. When used with sensitizing dyes, the ruthenium halide may be added before or after the addition of the dyes. The sensitive silver halide may be the bromide, chloride, or iodide or mixtures thereof, and the emulsion binder may be gelatine, collodion; albumen, a cellulose derivative, or a synthetic resin. Tables are given comparing the speed, gamma, and fog of the initial emulsion with the same emulsion stored under tropical conditions and in dry heat. Specifications 602,158 and 650,655 are referred to.