PHOTOGRAPHIC SPEED INCREASING AND LATENT IMAGE STABILIZING COMPOUNDS, SILVER HALIDE EMULSIONS, AND PHOTOGRAPHIC ELEMENTS

摘要

Photographic silver halide emulsions show increased speed and reduced latent image fading when a compound of the following structure is incorporated: < IMG > wherein: X is -O-, -S-, -Se-, or < IMG >; Y1 and Y2 individually represent hydrogen or an aromatic nucleus or together represent the atoms completing a fused aromatic nucleus, Z is < IMG > or < IMG >; R is hydrogen or lower alkyl of from 1 to 5 carbon atoms; and R1 is hydrogen or methyl.