Chromogenic leuco redox-dye-releasing compounds for photothermographic elements

A method of producing an image comprising:

• (a) imagewise exposing an element comprising a support bearing at least one heat-developable, photosensitive, image-forming photothermographic emulsion layer comprising:
• (i) a photosensitive silver halide;
• (ii) a non-photosensitive, reducible source of silver;
• (iii) a chromogenic leuco dye reducing agent;
• and
• (iv) a binder;
• wherein the leuco dye reducing agent comprises a chromogenic leuco dye compound of the general formula:
• ##STR19## wherein:
• (A) R is hydrogen or halogen;
• (B) R.sup.1 is a --C(O)--NH--A--Dye group, wherein:
• Dye represents the chromophore of a thermally mobile dye;
• and A represents a single bond or a divalent linking group of the formula --X--R.sup.5 --L--, wherein R.sup.5 is a divalent hydrocarbon chain containing up to 12 carbon atoms, L is a single bond or a divalent group that binds the chromophore of the thermally mobile dye to R.sup.5, and X is a single bond or an --SO.sub.2 -- group;
• (C) R.sup.2 is a hydrogen atom, an alkoxy group, an alkyl group, or a ballasting group;
• (D) R.sup.3 and R.sup.4 are each independently an aliphatic group, an aromatic group, a ballasting group, or a --Z--Y group, wherein Z is a alkylene group containing 1-4 carbon atoms, and Y is a cyano group, a halogen atom, an alkoxy group containing 1-20 carbon atoms, or --OH;
• and
• (E) Cp is a coupler group;
• and
• (b) heating the element to a sufficient temperature for a sufficient time to develop the image.