Rollei RPX-D is a new type of black and white film developer. RPX-D has been specially designed for Rollei RPX 400. It uses the nominal sensitivity of Rollei RPX 400 perfectly. RPX-D yields high acutance and excellent detail reproduction. RPX-D also yields high quality results when pushing. It even copes well with sensitivities of 800 and 1.600 ASA, with no visible change in the tonal value.