A new class of photographic developing agents of the p-aminophenol type are compounds of the formula: ##EQU1## wherein R.sup.1 is an alkyl group of 1 to 12 carbon atoms; R.sup.2 is an alkyl group of 1 to 12 carbon atoms or a sulfoalkyl group of 1 to 12 carbon atoms, R.sup.3 is a hydrogen atom or an alkyl group of 1 to 12 carbon atoms, R.sup.4 is a hydrogen atom or an alkyl group of 1 to 12 carbon atoms, and X.sup.- is an anion with the proviso that when R.sup.2 is a sulfoalkyl group then X.sup.- is the sulfo radical of R.sup.2. These compounds are useful as color developing agents, especially in diffusion transfer processes, and have been found to provide advantageous characteristics as compared with conventional developers of the p-amino-phenol type, for example, a substantial decrease in the formation of unwanted color stain in the receiving layer employed in diffusion transfer processes.