Patent GB-1379398-A (GB)
Title: Photographic colour material having an auxiliary silver halide layer
IPC: G03C7/30
Filed: 1971-12-21
Abstract: 1379398 Photographic material containing silver bleach inhibitor releasing compound EASTMAN KODAK CO 21 Dec 1971 [22 Dec 1970(2)] 59270/71 Headings G2C and G2E A colour photographic material comprises a support having thereon three picture-recording photographic colour-forming units, each of which comprises at least one light-sensitive silver halide emulsion layer, which units are so disposed and sensitized that each is sensitive to a different primary colour region of the visible spectrum and records respectively blue, green or red light, and comprises an auxiliary image-recording lightsensitive silver halide emulsion layer which has a speed and/or sensitivity and/or is separated from said units by a filter layer such that the auxiliary layer does not form a latent image upon latent image-forming exposure of the picture recording units and which contains a non-diffusible silver bleach-inhibitor-releasing (BIR) organic compound which is non-diffusible in a hydrophilic colloid layer in the presence of aqueous alkaline solution and which reacts in the auxiliary layer with oxidized developing agent to release a silver bleach inhibitor having a thiol or selenyl group and a molecular weight of at least 125 excluding the S or Se atom and which also satisfies a test disclosed in the Specification. The BIR compound may be a BIR hydroquinone which releases the silver bleach inhibitor by reaction with any oxidized developing agent or a BIR coupler which releases the silver bleach inhibitor by reaction with oxidized colour developing agent. The BIR coupler may have the Formula:- where COUP represents a photographic colour coupler radical substituted in its coupling position with the group -X-(A')-R' a ; a is O or I to 6; X is S or Se; R' is NO 2 , halogen, alkyl, substituted alkyl or cycloalkyl having 1-22C, cyclohexadienyl, optionally substituted aryl, a 3-22C thio group, a 4-22C amido group, a carboryl group, a carbamoyl group, alkoxy, benzyloxy or aryloxy; A' is carbonyl, thiocarbonyl, carboxymethylene, a carbocyclic ring containing 3-6C which can  form part of a fused ring structure or a 3-6 membered heterocyclic ring containing at least 1C and 1-5 atoms selected from N, O, S or Se which ring can have other carbocyclic or heterocyclic rings fused to it, the values of these symbols being subject to certain provisoes disclosed in the Specification. The BIR hydroquinone may have the Formula:-  where X, A' and R' a  are as above; R 30  and R 31  are each H or an alkaline splittable masking group; R 40 , R 41  and R 42  are each H, or optionally substituted alkyl or R 40  and R 41  together complete a fused benzene ring. The picturerecording units may have a minimum sensitivity in the region of the spectrum between the sensitivity peaks of adjacently sensitized picturerecording units and the auxiliary layer may be sensitized so that its sensitivity peak is in this region of minimum sensitivity. The auxiliary layer may contain a scavenger for oxidized developing agent, e.g. a competing coupler (see Example 1-6), which does not cause false colouration. The auxiliary layer may be a fogged, direct-positive silver halide emulsion layer.