GB1483093A - Photographic material - Google Patents

Abstract

1483093 Photographic materials producing dye images EASTMAN KODAK CO 2 Aug 1974 [2 Aug 1973 (4)] 34202/74 Heading G2C [ Also in Division C2] A photographic material for producing dye images comprises a support and a neutral or acid layer containing (a) a triazolium or a tetrazolium salt, (b) a compound which on exposure to U.V. or visible light in the presence of labile H atoms produces a reducing agent precursor activatable by alkali and (c) a source of labile H atoms (which may be compound (b) or a binder). The triazolium salt is preferably of formulae: wherein 2 completes a fused benzene or naphthalene ring, y is 1 or 2, R is aryl or arylene or a heterocyclic group of aromatic character, R<SP>1</SP> is aryl, alkyl or aromatic-like heterocyclic and X is an anion. The tetrazolium salt preferably contains electronegative substituents on the ring(s) which gives a formazan dye of enhanced stability and more preferably N-heterocyclic aromatic-like substituents in the 2- or 3-position which produce dyes which can produce tridentate chelates with metal salts. Specified compounds (b) are (i) nitroaryl compounds, (ii) aryl disulphides, (iii) phenazinium salts, (iv) diazoanthrones, (v) beta-keto-sulphides, (vi) quinones and (vii) dihydroquinones and quinones containing substituents (e.g. hydroxy-or alkoxy-alkyl, alkoxy, aminoalkyl, amino and N-hetero) which contains a labile H atom. Nitroaryl compounds (e.g. nitrobenzyl alcohol) can also contain labile H atoms. Specified sources (c) are (i) vinyl acetal or vinyl alcohol polymers, (ii) cellulose ethers and esters (iii) polyethylene glycol, (iv) alcohols and glycols, (v) nitrilo compounds and (vi) N- hydroxymethyl amides, the first three sources may also act as binders. The material also generally contains a binder and may be imagewise exposed using a mercury lamp to produce a latent image which is developed by application of ammonia or a volatile amine or an alkaline solution to produce a dye image. Alternatively, it is suggested that a compound which releases a base on heating may be present in the layer. The images may be fixed by uniform exposure.