Toning agents for use in thermographic recording materials

A process for providing an image on a monosheet thermographic recording material comprising (a) providing a monosheet thermographic recording material comprising a support and a thermosensitive element, the thermosensitive element comprising a substantially light-insensitive organic silver salt, a reducing agent therefor, a binder and at least one toning agent and (b) imagewise exposing the monosheet thermographic recording material, wherein the at least one toning agent is represented by formula (I):

• wherein R1 is an alkyl, an alkenyl, an alkynyl, a cycloalkyl, an alkaryl, an aryl, a non-aromatic heterocyclic or a heteroaryl group all of which may be optionally substituted;
• with the proviso that R1 may not be a hydrogen atom if both R2 and R3 are both hydrogen atoms;
• R2 and R3 are independently a hydrogen or a halogen atom or an amino, amide, ester, carboxy, carbonato, alkyl, alkenyl, alkynyl, cycloalkyl, alkaryl, aryl, non-aromatic heterocyclic or heteroaryl group all of which may be optionally substituted;
• R2 and R3 together represent the atoms necessary to complete a heteroaromatic ring with no more than one nitrogen atom, an alicyclic ring or a non-aromatic heterocyclic ring which all may be optionally substituted;
• and X is a carbonyl group, or is —N—R4, where R4 is an alkyl group.

A black and white monosheet thermographic recording material comprising a support and a thermosensitive element the thermosensitive element comprising a substantially light-insensitive organic silver salt, an organic reducing agent therefor in thermal working relationship therewith, photosensitive silver halide, a binder and at least one toning agent, wherein the at least one toning agent is represented by formula (I):

• wherein R1 is an alkyl, an alkenyl, an alkynyl, a cycloalkyl, an alkaryl, an aryl, a non-aromatic heterocyclic or a heteroaryl group all of which may be optionally substituted;
• R2 and R3 are independently a hydrogen or a halogen atom or an amino, amide, ester, carboxy, carbonato, alkyl, alkenyl, alkynyl, cycloalkyl, alkaryl, aryl, non-aromatic heterocyclic or heteroaryl group all of which may be optionally substituted;
• R2 and R3 may together represent the atoms necessary to complete a heteroaromatic ring with no more than one nitrogen atom, an alicyclic ring or a non-aromatic heterocyclic ring which all may be optionally substituted;
• X is a carbonyl group, or is —N—R5, where R5 is an alkyl group;
• and wit the proviso that R1 may not be a hydrogen atom if both R2 and R3 are both hydrogen atoms.