Patent ID: 7112399

Claim:
A black-and-white photothermographic material comprising a support and having on both sides thereof one or more of the same or different thermally developable imaging layers comprising a binder, and in reactive association, a photosensitive silver halide that is spectrally sensitized to a predetermined wavelength within a predetermined range of wavelengths, a non-photosensitive source of reducible silver ions, a reducing agent for said non-photosensitive reducible silver ions, and optionally an outermost protective layer disposed over said one or more thermally developable imaging layers, said material further comprising in a layer on one or both sides of said support, an opaque material that becomes transparent when heated to at least 120° C., said opaque material being dispersed within a hydrophilic binder or water-dispersible polymeric latex, and comprising polymeric microcapsules filled with water and derived from polymers derived from at least one styrene or acrylate monomer, or both.