Blue sensitizing dyes with heterocyclic substituents

摘要

A photographic element having a silver halide emulsion spectrally sensitized to blue light by a dye of formula (I) to have a maximum blue sensitivity at less than 485 nm. The dye allows the element to have good color reproduction while still providing good speed response despite the shorter blue sensitivity. Formula (I) is: wherein: X and X' each independently represent the atoms necessary to complete a thiazole, benzothiazole, naphthothiazole, oxazole, benzoxazole, naphthoxazole, selenazole, benzoselenazole, naphthoselenazole, imidazole, benzimidazole, or naphtho-imidazole, and X may be further substituted and X' substituted or unsubstituted; Z1 represents a pyrrole, furan or thiophene containing group; R1 and R2 each independently represent substituted or unsubstituted hydrocarbon containing 1 to 10 carbon atoms; and A represents a counter-ion as needed to balance a charge of the molecule.