High-speed direct-positive photographic elements utilizing core-shell emulsions

摘要

Direct-positive photographic elements are comprised of a support and a silver halide emulsion layer containing core-shell silver halide grains comprising a chemically sensitized core and a chemically sensitized shell, wherein at least one of the core and the shell comprises a band of dopant and wherein the dopant is hexacyano ruthenium (II). Preferably, the shell of the core-shell grains is chemically sensitized with both a gold-containing chemical sensitizing agent and a sulfur-containing chemical sensitizing agent and the weight ratio of the gold-containing chemical sensitizing agent to the sulfur-containing chemical sensitizing agent is at least about two to one.