DEVELOPER CONCENTRATE FOR BLACK AND WHITE DEVELOPMENT OF PHOTOGRAPHIC MATERIALS

摘要

The present invention relates to an aqueous developer concentrate for the black and white development of silver halide photographic materials, without hydroquinone, said developer concentrate having the advantage of remaining stable and not having a problem of precipitation during storage. The developer concentrate according to the invention comprises as main developer hydroquinonesulfonic acid or one of its salts, and as co-developer a mixture comprised of 4-methyl-4-hydroxyrnethyl-l-phenyl-3-pyrazolidone and at least one substituted 3-pyrazolidone type co-developer.