Patent GB-1464104-A (GB)
Title: Photographic silver  halide elements useful in colour diffusion  transfer  processes
IPC: G03C8/12
Filed: 1974-01-28
Abstract: 1464104 Photographic silver halide material EASTMAN KODAK CO 28 Jan 1974 [26 Jan 1973] 03800/74 Heading G2C A photographic material comprises a support and a silver halide emulsion, the emulsion having associated therewith in a layer which is permeable to an alkaline aqueous processing composition a compound of the Formula:- where R<SP>1</SP> is an aromatic ring; each of R<SP>2</SP> and R<SP>3</SP> is a bivalent organic group containing 1-3 atoms in the bivalent linkage; each of n and m is 1 or 2; Nu is an oxidizable nucleophilic group, i.e. an atom or group of atoms which have an electron pair capable of forming a covalent bond and which can be oxidized by oxidized silver halide developing agent, or a hydrolyzable precursor therefor; E is CO or SO 2 ; Q is a bivalent group providing a mono atom linkage between E and X 2  where the mono atom is a non-metallic atom of group VA or VIA of the MendelÚef periodic table in its 2- or 3- valence state; one of X 1  and Q-X 2  is a ballasting group of a size sufficient to render the compound immobile in the presence of the composition and the other of Xi and Q-X 2  is a photographically active moiety; Nu, R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, m and n being selected to provide such proximity of Nu and E as to permit intramolecular nucleophilic displacement reaction, i.e. a reaction in which a nucleophilic centre attached to a compound reacts at another site on the compound which is an electrophilic centre, to effect displacement of a group or atom attached to the electrophilic centre, and to provide 3-5 atoms between the atom which is the nucleophilic centre of the nucleophilic group and the atom which is the electrophilic centre of E whereby the compound is capable of forming a 5- to 7- membered ring on the displacement reaction, the displacement reaction taking place in the presence of the composition and resulting in cleavage of Q-X 2  from E, and the nucleophilic group being selected so that the rate of oxidation thereof by oxidized silver halide developing agent is greater than the rate of intramolecular nucleophilic displacement and the oxidation of the nucleophilic group preventing the nucleophilic displacement reaction, whereby, after imagewise exposure, processing of the material with the composition in the presence of the silver halide developing agent produces imagewise release of the moiety. R<SP>1</SP> may be a benzene ring and Nu a hydrolyzable precursor for a nucleophilic group of Formula -NR<SP>4</SP>-O-CO- which is bonded through the -CO- group to the aromatic ring to form a 2,1- benzoisooxazolone of the Formula:- where R<SP>4</SP> is optionally substituted alkyl having 1-10C or optionally substituted aryl having 6-20C or an alkali-hydrolyzable group; and m is 1. The compounds I to VIII specified are all azo dyes of the latter Formula where R<SP>4</SP> is CH 3 , X 1  is C 18 H 37 N(CH 3 )CO- or C 18 H 37 O-, n is 1, E is CO, Q is -N(CH3)- and X 2  is the azo dye containing moiety which is released imagewise as above. A colour image may be provided by the dye released in a diffusion transfer process, or by the immobile dye remaining in the initial location attached to the oxidized compound or both images can be used. In addition Examples 8 and 9 disclose compounds of the above Formula C- 1 and C-2 having releasable colour coupler and oxichromic moiety respectively used to form negative and positive dye images. The silver and silver halide remaining after development may be removed. The silver bromide grain size is specified in the Examples. The photographically active moiety may be a silver complexing agent, silver halide solvent,.toner, hardener, antifoggant, foggant, sensitizer, desensitizer, developer, oxidizing agent, development inhibitor, or development accelerator but no compounds containing these moieties are specified. In Example 4 the red-sensitive silver halide emulsion contains a magenta dye imageproviding compound of the above Formula.