Chemical sensitisation of silver halide emulsion for colour photographic material

摘要

Spectrally sensitised photographic silver halide emulsion is sensitised chemically by adding cyclic azetidine-2-thione or -2-selenone compound(s). The chemical sensitiser is of formula (I): X = sulphur or selenium; R1-4 = hydrogen, alk(en)yl, ar(alk)yl, heterocyclyl or a group with a carbonyl or (thio)ether function; or 2 of R1-3 = a group forming a condensed ring .