Blocked aliphatic thiol stabilizers for photothermographic materials

A black-and-white photothermographic material comprising a support and having thereon at least one photothermographic imaging layer comprising a hydrophilic polymer binder or a water-dispersible polymer latex binder and in reactive association:

• a. a photosensitive silver halide present as ultrathin tabular grains,
• b. a non-photosensitive source of reducible silver ions that comprises an organic silver salt comprising a silver salt of a nitrogen-containing heterocyclic compound containing an imino group,
• c. a reducing agent for said reducible silver ions that is an ascorbic acid derivative,
• d. a blocked aliphatic thiol compound that is one or more compounds of Structures PS-1 through PS47, said blocked aliphatic thiol compound being present in an amount of from about 5 mg/m2 to about 500 mg/m2, and
• e. boric acid or a boric acid ester compound.

A black-and-white photothermographic material comprising a support having on a frontside thereof,

• a) one or more frontside photothermographic imaging layers comprising a hydrophilic polymer binder or a water-dispersible polymer latex binder, and in reactive association, a photosensitive silver halide, a non-photosensitive source of reducible silver ions, and a reducing agent for said non-photosensitive source reducible silver ions,
• b) said material comprising on the backside of said support, one or more backside photothermographic imaging layers having the same or different composition as said frontside photothermographic imaging layers, and
• c) optionally, an outermost protective layer disposed over said one or more photothermographic imaging layers on either or both sides of said support,
• wherein said material comprises one or more of the same or different blocked aliphatic thiol compounds on both sides of said support, each of said blocked aliphatic thiol compounds being present in the same or different amount of at least 1 mg/m2 on both sides of said support, said blocked aliphatic thiol compound having a calculated octanol-water partition coefficient (c log P value) of 2.0 or greater, and an N value equal to or greater than 6.5.