Patent GB-953454-A (GB)
Title: Improvements in photographic processes
IPC: G03C7/32
Filed: 1960-04-06
Abstract: 953,454. Photographic materials and developers for dye image production. KODAK Ltd. April 6, 1960 [April 6,1959; June 3,1959], No. 12109/60. Heading G2C. A support bears at least one light-sensitive silver halide emulsion layer having therein, or in an adjacent layer, either (a) a preformed development-inhibitor-releasing non-diffusible coupler, or (b) a non-preformed development-inhibitorreleasing coupler, the said couplers being capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye and a compound capable of inhibiting the development of silver halide by the developing agent. Couplers stated to be of these types are described in numerous classes and subclasses with structural formulae in some instances, about 74 specific couplers are quoted and uses thereof include control of contrast, speed, grain and image sharpness, colour correction and formation of masking images. The claims also embrace processes wherein an exposed image is developed in the presence of one of the specified couplers and developer compositions comprising a primary aromatic amino developer and such a coupler from which the released inhibitor is a mercaptan. The term "coupler" includes colourless (i.e. competing) couplers. Example 1 describes two films having respectively the couplers 3-carboxymethyl-5- (4-dodecyloxyphenylazo) rhodanine and 1-hydroxy- 4-(4-beazotriazolyl azo) -N-[8-(2, 4-di-t-amylphenoxy)butyl] -2-naphthamide in layers underlying silver halide emulsion layers and a colour developing mixture thereof which is stated to produce an improvement in image sharpness as compared with a control, the images being of silver. Example 2 describes the production of red-sensitive films containing cyan-forming couplers overcoated with green-sensitive layers containing the development-inhibiting substances of the invention and reduction of gamma in the red-sensitive emulsions caused thereby. Examples 3, 4 are concerned with use of the couplers of the invention in developing solutions to control grain and contrast of silver and dye images respectively; Examples 5, 6 colour correction in multilayer films. Example 7 this in a multilayer packet film and Example 8 in a multilayer film including fogged emulsion layers. Example 9 reverts to the use of coupler in a developer, Example 10 describes use of the couplers to reduce grain size, and Examples 12, 13 transfer procedure using zinc sulphide nuclei layers. The light-sensitive materials which are claimed in Specification 932,272 comprising a support bearing a light-sensitive silver halide emulsion-layer, contiguous thereto a developable silver halide emulsion containing a non-diffusing colourant capable of reacting with oxidised developer. To form a diffusible colourant, and closely associated with the light-sensitive emulsion layer a compound (usually a coupler) containing a development inhibiting "moiety" (sic) capable of being split off by oxidised developer to form a diffusible development inhibitor is disclaimed. Specifications 680,488, 711,488, 755,655, 798,512, 840,731, 904,364 and 912,258 also are referred to.