Abstract: A thermographic element comprising in a non-aqueous binder medium a silver salt oxidizing agent in reactive association with a compound comprising a plurality of redox color releasing moieties such that oxidation of each redox color releasing moiety causes release from said compound of a thermally diffusible dye.The compounds many of which are new incorporate two or more developer moieties into a single molecule to minimize the diffusibility of the compound. Following oxidation, either directly by the silver salt or by means of a cross-oxidizing agent, each oxidized developer moiety releases a thermally diffusible dye. The compounds are of sufficient size and molecular weight to slow or prevent diffusion in imaging systems and yet possess several active developer moieties per molecule which is advantageous over known ballasted dye releasers which comprise bulky molecules with only a single developer moiety.

Abstract: A photothermographic element comprising a support bearing at least one heat-developable, photosensitive, image-forming photothermographic emulsion layer comprising:(a) a photosensitive silver halide;(b) a non-photosensitive, reducible source of silver;(c) a reducing agent for the non-photosensitive reducible silver source; and(d) a binder;wherein the reducing agent is a hydrazide redox-dye-releasing compound of the general formulae: ##STR1## wherein: D represents the chromophore of a thermally mobile dye; X represents a single bond or a divalent linking group; R.sup.1 and R.sup.2 independently represent an organic group; and n.gtoreq.1.

Abstract: A photothermographic element comprising a support bearing an image forming system comprising:(a) a photosensitive silver halide(b) an organic silver compound(c) a polymer binder and(d) a reducing agent for the organic silver compound, characterized in that the reducing agent comprises a redox-dye-releasing compound of the general formula: ##STR1## in which: R represents an organic group which may be oxidatively cleaved to a thermally immobile form,A represents a bond or a divalent linking group having a chain consisting of up to 12 atoms, which is linked to the carbonyl group via a carbon atom or an oxygen atom, andD represents the chromophore of a thermally mobile dye.

Abstract: A photothermographic element comprising:(A) a coating comprising a support bearing a photothermographic medium, the medium comprising a light sensitive silver halide in reactive association with a silver salt of an organic acid and a color generating reducing agent which is a leuco compound which is oxidizable by silver ions into a colored dye of the general formula: ##STR1## in which: n=0, 1 or 2,R.sup.1 represents H, CN, lower alkyl of 1 to 5 carbon atoms, aryl or COOR.sup.6 in which R.sup.6 is lower alkyl of 1 to 5 carbon atoms or aryl,R.sup.2 and R.sup.3 independently represent CN, NO.sub.2, COOR.sup.6, SO.sub.2 R.sup.6, CONHR.sup.6 in which R.sup.6 is as defined above or R.sup.2 and R.sup.3 together represent the necessary atoms to form a 5- or 6-membered carbocyclic or heterocyclic ring having ring atoms selected from C, N, O and S atoms, whch carbocyclic or heterocyclic rings possess at least one conjugated electron withdrawing substituent,R.sup.4 and R.sup.

Abstract: A photothermographic element comprising a support bearing a photothermographic medium, the medium comprising a light sensitive silver halide in reactive association with a silver salt of an organic acid and a color generating reducing agent which is a leuco compound which is oxidisable by silver ions into a colored dye of the general formula: ##STR1## in which: n=0, 1 or 2,R.sup.1 represents H, CN, lower alkyl of 1 to 5 carbon atoms, aryl or COOR.sup.6 in which R.sup.6 is lower alkyl of 1 to 5 carbon atoms or aryl,R.sup.2 and R.sup.3 independently represent CN, NO.sub.2, COOR.sup.6, SO.sub.2 R.sup.6, CONHR.sup.6 in which R.sup.6 is as defined above or R.sup.2 and R.sup.3 together represent the necessary atoms to form a 5- or 6-membered carbocyclic or heterocyclic ring having ring atoms selected from C, N, O and S atoms, which carbocyclic or heterocyclic rings possess at least one conjugated electron withdrawing substituent,R.sup.4 and R.sup.

Abstract: Photothermographic elements containing heat bleachable acutance/antihalation dyes and thermographic elements employing heat bleachable dyes of the formula: ##STR1## in which: n is 2, 3, 4 or 5,at least one of R.sup.1 to R.sup.4 represent hydrogen and the remainder of R.sup.1 to R.sup.4 independently represent a hydrogen atom, an optionally substituted cycloalkyl group, an optionally substituted alkenyl group, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heterocyclic aromatic group, or R.sup.1 and R.sup.2 together or R.sup.3 and R.sup.4 together represent the necessary atoms selected from C, N, O and S to complete a non-aromatic type ring,X.sup..crclbar. is an anion.

Abstract: A photothermographic element comprising a reflective base having coated thereon one or more layers constituting a photothermographic imaging medium in which a bleachable antihalation medium is coated over said photothermographic imaging medium, the components of the antihalation medium being in non-reactive association with components in the photothermographic imaging medium. The topcoat antihalation layer allows a wide latitude in the selection of dye bleach systems and binders and surprisingly is at least as effective as the use of antihalation underlayers.

Abstract: An imagewise bleachable composition is described comprising a dye in reactive association with a mesoionic compound. The composition may be bleached by radiation at wavelengths between 200 and 1000 nm.