Photographic emulsions.

摘要

There is described a silver halide emulsion which comprises a colloid medium having dispersed therein silver halide emulsion crystals which comprise at least two layers of different silver halide composition, there being sub-developable silver centres present at the boundary between two of the layers which have been formed by a reduction process. By sub-developable centres is meant small clusters of silver atoms which increase the inherent light sensitivity of the silver halide grains but which do not contribute substantially to the formation of fog when unexposed silver halide crystals are developed.