Coloured photographic images - by transferring colourless reagent from exposed silver halide emulsion to form image in register

Coloured transfer images are produced by (a) imagewise exposing with electromagnetic radiation of a photographic material contg a silver halide emulsion layer which is sensitive or sensitised towards the electromagnetic radiation, and contains a developer which is diffusion resistant and is in a hydrophilic colloid medium, and contains, in active contact with the developer, at least one colourless reagent which is capable of (1) diffusing in an aqs. alkaline medium from this material to a receiving material, (2) forming a dye by oxidative, intermolecular or intramolecular coupling with another colourless reagent which can also diffuse in an aq. alkaline medium, and (3) forming with the oxidn pdt of the developer a cpd which is considerably more diffusion resistant than in the unreacted state, (b) contacting the exposed photographic material with an aq. alkaline activating liq in order to promote the reducing action of the developer, so that in the exposed parts a silver image and an oxidn pdt of the developer are formed this oxidn pdt coupling with the colourless reagent so as to form in the exposed parts of the emulsion layer one or more cpds which are more diffusion resistant than the unreacted reagent, and (c) transferring from the heated material an amt of reagent(s) which is capable of diffusion through an alkaline treatment liq to a registering material on which the transferred reagent is oxidatively coupled with an oxidant which is stronger than exposed silver halide, so that a coloured image is formed on the receiving material.