Nucleated silver halide emulsions contg - quaternary salts

摘要

Emulsion contains a quaternary salt of formula: where Z completes a 5- or 6-membered ring; j is 1 or 2; g is 1 - 5; R' is H, alkyl, alkylthio or aryl; R is formul, hydrazonoalkyl ro -CHT'(T2); T~ and T2 are alkoxy, alkylthio or together complete a cyclic acetal; and X rho is an anion. The emulsion may be a direct positive emulsion forming an internal latent image.