An aqueous alkaline photographic silver halide developer composition comprising a dihydroxy benzene developing agent, an auxiliary superadditive developing agent, an antifogging agent, an antioxidant and a buffering agent, characterized by the fact that the composition further comprises a stabilizing amount of an .alpha.-ketocarboxylic acid.The developer composition has a better resistance against air oxidation and can be left in continuous transport automatic processors for several days without undergoing any substantial decrease of its developing properties.The developer composition is particularly useful in a process for the formation of a high contrast silver image by developing silver halide photographic elements including at least a negative acting surface latent image type silver halide emulsion in the presence of a hydrazine compound, preferably in the additional presence of an effective amount of a contrast promoting agent.