Abstract: An improved photographic developing composition, for use in development of a black-and-white silver halide photographic element, is comprised of at least one developing agent and, in an amount sufficient to inhibit sludge deposition, mercapto thiadiazole glycerol propoxylate. The developing composition is broadly useful in black-and-white development but is most advantageously employed in a process for forming a high-contrast image utilizing a silver halide photographic element comprising a hydrazine compound which functions as a nucleating agent and an amino compound which functions as an incorporated booster.