Photographic Colour Transfer Process

1, 157, 503. Photographic colour transfer process. ILFORD Ltd. Sept. 8, 1966 [Sept. 10, 1965], No. 38748/65. Heading G2C. [Also in Division C4] A photographic transfer process giving positive colour images comprises image-wise exposing a photographic element having a supported lightsensitive silver halide emulsion layer containing in the emulsion, or in a layer adjacent thereto, an immobile coloured or colourless colour coupler having the general formula given below which becomes diffusible at a certain pH, developing with an alkaline processing solution which contains a colour developing agent and has a pH high enough to solubilize the colour coupler, contacting the element with a receptor element and after at least 1 minute separating the elements to obtain, when a coloured coupler is used, a positive colour image on the receptor element. When the coupler is colourless the colour developing agent is oxidized, simultaneously or subsequently to contacting the elements, to form a positive colour image in the receptor element. The coloured or colourless colour coupler is of the general formula:- where R is a group containing a colour coupling function, X is a trivalent or tetravalent radical of the formula:- wherein the bonds (a) and (b) form part of the imide ring and either or both of bonds (c) and (d) are linked to the colour coupling function R, and R 1 is alkyl of 1-10 carbons or an aryl or aralkyl group optionally substituted by alkyl of 1-10 carbons. Alternatively, in the development step the pH of the alkaline processing solution containing the colour developing agent is high enough for development to take place but not high enough to solubilize the coupler, and the element is then treated, after allowing development to take place, with a second alkaline solution of pH high enough to solubilize the coupler and contacted with the receptor element as before. The second alkaline solution may be applied in the presence of a development restraining substance.