Thermographic recording material with improved image tone

Process for using a compound according to formula (I):

• wherein R1 is hydrogen, an alkali metal ion, an ammonium ion, a phosphonium ion, a sulphonium ion, an alkaline earth ion or an optionally substituted alkyl, cycloalkyl, heterocyclic, alkaryl, aralkyl, heteroaryl or aryl group;
• R2 is an optionally substituted alkyl, cycloalkyl, heterocyclic, alkaryl, aralkyl, heteroaryl or aryl group;
• or R1 and R2 together represent the atoms necessary to form a ring structure;
• and
• X is hydrogen, an alkali metal ion, an ammonium ion, a phosphonium ion, a sulphonium ion or an alkaline earth ion;
• in a substantially light-insensitive thermographic recording material as an image tone stabilizer, comprising the steps of:
• providing said substantially light-insensitive thermographic recording material comprising a support and a thermosensitive element, said thermosensitive element containing at least one substantially light-insensitive organic silver salt, an organic reducing agent therefor in thermal working relationship therewith, said compound according to formula (I) and a binder;
• and
• imagewise-applying heat to said substantially light-insensitive thermographic recording material.