Abstract: A heptamethine cyanine dye in which both nitrogen atoms of the cyanine chromophore bear a carboxyalkyl substituent comprising an alkyl chain of at least five carbon atoms. The dyes are useful as sensitisers in photothermographic imaging materials.

Abstract: Compounds suitable for use as antihalation or acutance dyes in silver halide photographic emulsions having a nucleus of the general formula (I), ##STR1## in which: Y and Z independently represent the non-metallic atoms necessary to complete a carbocyclic or heterocyclic ring or a fused ring system,M.sup..sym. is a cation, and,X represents the non-metallic atoms necessary to complete a 5-, 6- or 7- membered carbocyclic ring, a 5-,6- or 7- membered heterocyclic ring or a fused ring system on a 5-, 6- or 7- membered nucleus and comprising up to 14 total ring atoms selected from C,N, 0, S and Se.

Abstract: Cyanine dyes are disclosed having a nucleus of the formula: ##STR1## wherein; A and B are independently selected from the group consisting of heterocyclic ring nuclei and heterocyclic fused ring nuclei so as to complete a cyanine dye,m and n independently have values of 0, 1, 2 or 3 with the proviso that 2.ltoreq.m+n.ltoreq.4,R is selected from the group consisting of hydrogen, alkyl groups and aryl groups, each of which groups may be substituted, andQ represents those non-metallic atoms necessary to complete a nucleus selected from the group consisting of heterocyclic ring nuclei, carbocyclic ring nuclei, heterocyclic fused ring nuclei and carbocyclic fused ring nuclei.

Abstract: Infra-red sensitizing dyes for silver halide having a nucleus of the general formula: ##STR1## in which Q represents Cl or Br,R.sup.3 represents an alkyl or substituted alkyl,n is 0, 1, 2 or 3,X is an anion of molecular weight up to 400 which may be incorporated in one R.sup.3 group.

Abstract: Infra-red sensitizing dyes for silver halide having a mucleus of the general formula: ##STR1## in which: Q represents Cl or Br,R.sup.3 represents an alkyl or substituted alkyl,n is 0, 1, 2 or 3,X is an anion of molecular weight up to 400 which may be incorporated in one R.sup.3 group.

Abstract: Presensitized sheets for color proofing comprising a removable carrier sheet bearing a photosensitive medium sensitive to radiation within the wavelength band 325 to 700 nm and comprising photohardenable, photoadherent, photoinsolubilisable or photosolubilisable material, the sheet including a removable antihalation layer which is removed either when stripping the carrier sheet or during subsequent processing. The antihalation dyes may be positioned within a transparent carrier sheet, in a layer on the carrier sheet opposite to the photosensitive medium or in a layer positioned between the carrier sheet and light-sensitive medium.

Abstract: High contrast negative acting silver halide emulsions suitable for laser scanning applications comprising a Group VIII metal compound and one or more spectrally sensitizing dyes of the formula ##STR1## The emulsions have good long term stability and good sensitivity.

Abstract: A photographic element of the conventional wet processed type or of the dry silver type which includes an antihalation or acutance dye which absorbs in the near infrared and has a relatively low visible absorption while retaining a high extinction coefficient at .sub.max. The dye is of the general formula: ##STR1## in which: m+p=2,n is 0 or 1,s is 0 or 1,Z.sup.1 and Z.sup.2 independently represent the non-metallic atoms necessary to complete a heterocyclic nucleus of the type present in cyanine dyes,R.sup.1 and R.sup.2 independently represent an alkyl or substituted alkyl, alkenyl, substituted alkenyl or aralkyl group of up to 20 carbon atoms,R.sup.3 and R.sup.4 independently represent a hydrogen atom or an alkyl, substituted alkyl, alkenyl or substituted alkenyl group of up to 10 carbon atoms,R.sup.5, R.sup.6, R.sup.7 and R.sup.

Abstract: Images produced in photothermographic emulsions using silver halide as a light-sensitive material therein suffer from light scattering effects on the silver halide.Acutance dyes, many of which are novel, are disclosed which can absorb scattered light and which are bleached at the development temperature of the photothermographic composition.