Ciba-geigy Ag

David L Reeves

William E Long

Rainer Kitzing

Brian R Whitear

Glenn P Wood

Leslie F Mason

Terence C Webb

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

Novel azo compounds and their preparation are provided. These compounds have the general formula ##STR1## wherein X is N or CR.sub.4 where R.sub.4 is a hydrogen atom or an optionally substituted alkyl or aryl group, Y is S.sup..sym., N.sup..sym. R.sub.5, O.sup..sym. or N where R.sub.5 is an optionally substituted alkyl or aryl group, R.sub.1 is an optionally substituted alkyl or aryl group, R.sub.1 is a substituted aromatic or heterocyclic group containing a ballasting group, R.sub.2 and R.sub.3 are each hydrogen or alkyl groups having 1 to 4 carbon atoms, or R.sub.2 and R.sub.3 together with the nitrogen atom complete a heterocyclic ring, or one of R.sub.2 or R.sub.3 can be hydrogen and the other of R.sub.2 or R.sub.3 can be aryl. There may be further substitution in either of the benz rings and these rings may be benzannelated. These azo compounds are useful in the photographic field especially in the photographic dye diffusion transfer process for the production of photographic images.

Azo compounds useful in a photographic dye diffusion transfer process

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.

A light-sensitive photographic material is provided which comprises, coated on a photobase, at least one silver halide emulsion layer, said emulsion layer or a layer adjacent thereto containing a development inhibitor releasing compound of the formula ##STR1## wherein R.sub.1 is substituted phenyl which contains a ballasting alkyl group, R.sub.2 represents the atoms necessary to complete a five or six membered heterocyclic ring system which may be further substituted and R.sub.3 is an aryl or heterocyclic radical, any of which ring systems may be further substituted, the group --S--R.sub.3 being a development inhibiting group.

Light sensitive photographic material containing development inhibitor

Novel azo(hydrazo)-anthraquinone compounds and their preparation are provided. These compounds are of the general formula ##STR1## where R is hydrogen or at least one substituent, T.sub.1 is hydrogen, an hydroxy or alkoxy group or an amino or substituted amino group, R.sub.1 is hydrogen or halogen, an alkoxy, an amino or substituted amino group, an aryl or substituted aryl group, or a group conferring solubility in water and R.sub.2 is a group which comprises an azo linkage and a ballasting group or is a group which completes the hydrazo link and which comprises a ballasting group. The new compounds are useful in the photographic field, especially in the photographic dye diffusion transfer process for the production of photographic images.

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Brentwood, United Kingdom

David L Reeves