Patent ID: 6576414
Filing Date: 2003-06-10
Classification: G03C,Y10S

Abstract:
A color photothermographic element having on a support at least three light-sensitive color imaging layers which have their individual sensitivities in different wavelength regions, each of said imaging layers comprising a light-sensitive silver emulsion, a binder, a dye-providing coupler, and a developer or developer precursor, the dyes formed from the dye-providing couplers in the layers being different in hue, therefore capable of forming at least three dye images of different visible or non-visible colors,wherein at least one imaging layer comprises core/shell particles of non-light sensitive organic silver salts, the particles comprising (i) an outside shell comprising at least one organic silver salt, and (ii) under the outside shell, an underlying particle that comprises a core comprising at least one organic silver salt and, optionally, one or more intermediate shells each comprising at least one organic silver salt, wherein the outside shell is defined as the outermost shell that substantially covers the underlying particle; said at least one organic silver salt in the outside shell comprising a first organic silver salt and said at least one organic silver salt in the underlying particle comprising a second organic silver salt, wherein said first organic silver salt and said second organic silver salt are different, and the pKsp of said first organic silver salt is at least 0.5 lower than the pKsp of said second organic silver salt.