Ciba-Geigy Ag

Leslie F Mason

William E Long

Rainer Kitzing

Brian R Whitear

Glenn P Wood

David L Reeves

Matthias Schellenberg

Christoph Chylewski

Robert Stanley Cook

David Kilcast

A photographic dye diffusion transfer process is provided which operates by imagwise release of a dye. The dye diffuses to a receiving layer and is mordanted there to give a dye image. The dyes are released from a compound of the formula D--E--F--BAL by reductive cleavage. D is a group which contains the residue of diffusible dye, BAL is a ballasting group which renders the compound containing it substantive to the layer in which it is present, D and E being joined by any type of chemical bond and E and F represent a single or double bond system which links D and BAL and which has a reduction potential above -200 mV measured against a standard hydrogen electrode at a pH of less than 3 and which bond can be reductively cleaved at a pH of less than 3 by a reducing agent which is able to act as a pH below 3.

Process for the production of photographic images by dye diffusion

A new method to produce photographic images is provided which comprises

Process for producing photographic images

A photographic dye diffusion transfer process is provided which operates by imagwise release of a dye. The dye diffuses to a receiving layer and is mordanted there to give a dye image. The dyes are released from a compound of the formula D--E--F--BAL by reductive cleavage. D is a group which contains the residue of diffusible dye, BAL is a ballasting group which renders the compound containing it substantive to the layer in which it is present, D and E being joined by any type of chemical bond and E and F represent a single or double bond system which links D and BAL and which has a reduction potential above -200 mV measured against a standard hydrogen electrode at a pH of less than 3 and which bond can be reductively cleaved at a pH of less than 3 by a reducing agent which is able to act at a pH below 3.

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Brentwood, United Kingdom

Leslie F Mason