Patent ID: 6403295
Filing Date: 2002-06-11
Classification: G03C

Abstract:
A process for preparing a silver halide photographic emulsion comprising triangular tabular grains having (111) face as a main plane and a silver bromide content of 70 mol-% or more incorporated therein in a proportion of 60% or more of all silver halide grains contained therein as calculated in terms of projected area, said triangular tabular grains each having a thickness of less than 0.05 &mgr;m and an equivalent diameter of 0.6 &mgr;m or more as calculated in terms of circle, which comprises steps of nucleation, ripening and growth, wherein at least one of compounds represented by formulae (I) (II) and (III) is not present during nucleation but is present during ripening and growth: wherein R1 represents an alkyl group, alkenyl group or aralkyl group; R2, R3, R4, R5 and R6 each represent a hydrogen atom or substituent; R2 and R3, R3 and R4, R4 and R5 and R5 and R6 may be condensed to each other, with the proviso that at least one of R2, R3, R4, R5 and R6 represents an aryl group; and X represents a counter anion; wherein A1, A2, A3 and A4 may be the same or different and each represent a nonmetallic element required to form a nitrogen-containing heterocyclic group; B represents a divalent connecting group; m represents an integer of 0 or 1; R1 and R2 each represent an alkyl group; X represents an anion; and n represents an integer of from 0, 1 or 2, with the proviso that when the compound is an intramolecular salt, n is 0 or 1.