Fogged direct-positive silver halide emulsion containing a cyanine dye having an indole or indolenine nucleus substituted with a benzoyl or a phenylsulfonyl group

Claim 1

A light-sensitive, fogged direct positive silver halide emulsion characterized in that it contains a sensitizing amount of cyanine dye corresponding to one of the following formulae: ##STR55## wherein: m represents a positive integer of from 1 to 2; n represents a positive integer of from 2 to 4; R, r 6 each represent a benzoyl group or a phenylsulfonyl group; R 1 , r 1 ', r 2 and R 7 each represent a substituted or non-substituted acyclic hydrocarbon substituent; an alkyl-aryl substituent or an aryl substituent; R 3 represents an aryl or substituted aryl group; R 4 represents an hydrogen atom, an alkyl group having from 1 to 4 carbon atoms, an aryl group, a thienyl group, with the proviso that at least one of the two substituents R 4 is an hydrogen atom; R 5 represents an hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, an halogen atom, a nitro group, a benzoyl group or a phenylsulfonyl group; R 8 , r 9 each represent an alkyl group containing from 1 to 4 carbon atoms; X - represents an acid anion; and Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms in the heterocyclic ring, said non-metallic atoms being selected from the group consisting of carbon, oxygen, sulfur, nitrogen, and selenium atoms.