Core/shell silver donors for photothermographic systems comprising an oxidatively more reactive shell

摘要

The present invention is directed to a photothermographic element comprising silver halide, a blocked developer, a coupler, and core/shell particles, each such particle comprising a mixture of at least two non-photosensitive organic silver salts, which particle comprises a center portion comprising a non-photosensitive first organic silver salt and at least one shell portion covering the center portion, the shell comprising a non-photosensitive second organic silver salt. The organic silver salt in the shell has a lower pKsp relative to the organic silver salt in the core. This invention also provides a composition comprising the core/shell non-photosensitive organic silver salt particles, and a method of making the particles.