Patent ID: 7393626

Claim:
A black-and-white photothermographic material that forms a black-and-white image by a silver image, the black-and-white photothermographic material comprising, on one surface of a substrate, photosensitive silver halide grains having a core/shell structure, a non-photosensitive organic silver salt, a reducing agent and a binder, wherein said photosensitive silver halide grains include at least iridium and a metal selected from the group consisting of iron, copper, rhodium and ruthenium, an amount of iridium in the silver halide grains is from 1×10 −8 to 1×10 −2 mol per 1 mol of silver halide, an amount of the metal selected from the group consisting of iron, copper, rhodium and ruthenium in the silver halide grains is from 1×10 −8 to 1×10 −2 mol per 1 mol of silver halide, and 90% or more of a total iridium amount contained in the silver halide grains is contained in a core portion of the grain providing that, the core portion of the grain corresponds to 50% of the total mol % of silver halide in the grain, and at least 50% of a total amount of the metal selected from the group consisting of iron, copper, rhodium and ruthenium contained in the silver halide grains is contained in the shell portion of the grain, wherein the reducing agent is a bisphenol compound represented by the following formula (R): wherein, in formula (R), R 11 and R 11 ′ each independently represents an alkyl group with 1 to 20 carbon atoms; R 12 and R 12 ′ each independently represents a hydrogen atom or a substituent that can substitute the benzene ring; L represents —S— or —CHR 13 —; R 13 represents a hydrogen atom or an alkyl group with 1 to 20 carbon atoms; and X 1 and X 1 ′ each independently represents a hydrogen atom or a group that can substitute the benzene ring; and wherein the silver halide is silver bromide, silver iodobromide or silver iodide.