Pyrazolo [1,5A]benzimidazole photographic colour couplers.

摘要

A photographic non-diffusible magenta dye-forming colour coupler which is a 2-alkoxypyrazolo[1,5-a]-benzimidazole, for example a dye of the formula: <CHEM> wherein R<1> to R<4> are each hydrogen or a substituent, R<5> is an alkyl or substituted alkyl group, and X is hydrogen or a coupling-off group, and wherein at least one of R<1> to R<5> or X contain a ballast group capable of rendering the coupler non-diffusible in photographic layers.