GB1466050A - Silver halide photographic materials - Google Patents

Abstract

1466050 Silver halide material FUJI PHOTO FILM CO Ltd 12 March 1975 [12 March 1974] 10387/75 Heading G2C A light-sensitive silver halide photographic material comprises a support having thereon a silver halide emulsion layer in which at least 50% by number of the silver halide grains have a (100) crystal habit, at least one of the photographic layers of the material comprises a compound of Formula 1. in which R<SP>1</SP> represents an optionally substituted aliphatic hydrocarbon group or an aryl group, and each of R<SP>2</SP> and R<SP>3</SP> represents a hydrogen atom or an aliphatic or aryl group or R<SP>2</SP> and R<SP>3</SP> together represent a divalent aliphatic group which completes a 5- or 6-membered ring, and at least one of the polymethine dyes represented by the general Formulae II and III. wherein each of Z<SP>1</SP> and Z<SP>2</SP> represents a group of atoms necessary to complete an optionally substituted benzothiazole, naphthothiazole, benzoselenazole or naphthoselenazole nucleus; A represents an alkyl group; each of R<SP>4</SP> and R<SP>5</SP> represents an aliphatic group; x # represents an anion; and n is 0 or 1, n being 0 when an internal betaine-type salt is formed; wherein Z<SP>3</SP> represents the atoms necessary to complete an optionally substituted oxazoline, oxazole, benzoxazole, naphthoxazole, thiazoline, thiazole, benzothiazole, naphthothiazole, benzoselenazole, pyrroline, tetrazole, pyridine or quinoline nucleus, Q represents the atoms necessary to complete a 2-thioxazolidinedione, 2-thiohydentoin or rhodanine nucleus, R<SP>6</SP> represents an aliphatic group L represents an optionally substituted methine group and each of p and q is 0 or 1. The sensitivity to low illuminance for long exposure times is improved. The silver halide grains may have an average grain size from 0À04Á to 2Á, especially 0À1Á to 0À7Á. In Examples (i) an emulsion containing 80% of silver halide crystals of (100) habit is prepared by mixing solutions of gelatin, silver nitrate and potassium bromide and iodide while adjusting the p Ag to 8À8 during the formation of the silver grains, washing, ripening and adding chlorauric acid and sodium thiosulphate sensitizers. A comparison emulsion prepared at p Ag 9À5 has 80% of the grains with the (iii) crystal habit. To the emulsions compounds of types I, II and III are added and tests carried out with exposures of 10<SP>-4</SP> and 10 seconds.