Heat developable photosensitive composition and a heat developable photosensitive member having a layer comprising the composition

DETAILED DESCRIPTION What is claimed is: 1.
A heat developable photosensitive composition adapted to form metallic silver grains at exposed portions in cooperation with a reducing agent comprising an organic silver salt, a halide and, as a compound to enhance formation of metallic silver grains at exposed portions and suppress formation of metallic silver grains at non-exposed portions, at least one member of sulfur compounds having the formula (1): ##STR91## in which Y is selected from the class of hydrogen, alkyl, unsubstituted or substituted phenyl, aralkyl and ##STR92## wherein R.
sub.
7 is benzyl, Z is one or more atoms necessary for forming a 5- or 6-membered heterocyclic ring which may be substituted or unsubstituted.
2.
A heat developable photosensitive composition according to claim 1 in which Y is an alkyl having 1-6 carbon atoms.
3.
A heat developable photosensitive composition according to claim 1 in which Y is benzyl.
4.
A heat developable photosensitive composition according to claim 1 in which the sulfur compound is contained in an amount of 10.
sup.
-4 -10.
sup.
-1 part by weight per one part by weight of the organic silver salt.
5.
A heat developable photosensitive composition according to claim 1 in which the sulfur compound is contained in an amount of 5.
times.
10.
sup.
-4 -10.
sup.
-2 parts by weight per one part by weight of the organic silver salt.
6.
A heat developable photosensitive member adapted to form metallic silver grains at exposed portions comprising a layer containing a reducing agent and a layer containing an organic silver salt, a halide, an insulating medium and as a compound to enhance formation of metallic silver grains at exposed portions and suppress formation of metallic silver grains at non-exposed portions, at least one member of sulfur compounds having the formula (1): ##STR93## in which Y is selected from the class of hydrogen, alkyl, having 1-6 carbon atoms, unsubstituted or substituted phenyl, benzyl ##STR94## wherein R.
sub.
7 is benzyl, Z is one or more atoms necessary for forming a 5- or 6-membered heterocyclic ring which may be substituted or unsubstituted, the former layer overlying the latter layer