The project has investigated the degradation products of colour developing agents CD-3 and CD-4 that are likely to be present as significant constituents in used colour developer solutions. Some of the major components have been identified and confirmed earlier proposals made on model systems of solutions of developing agents. Liquid chromatographic and capillary electrophoretic methods have been established for the determination of the individual components of the developer solutions and both Kodak and competitor products have been examined.