Direct positive photographic photosensitive materials

Abstract

Disclosed are direct positive photographic photosensitive materials which have at least one internal latent image core/shell type silver halide emulsion layer, which has not been pre-fogged, on a support wherein the silver halide molar ratio of the core and shell of the emulsion is not more than 1/5, and wherein at least one type of compound which can be represented by the formula (N-I) indicated below is included in the photosensitive material. ##STR1## In this formula, Z represents a non-metal atomic group which is required to form a 5- or 6-membered heterocyclic ring, and Z may be substituted with substituents. R.sup.1 is an aliphatic group, and R.sup.2 is a hydrogen atom, an aliphatic group or an aromatic group. R.sup.1 and R.sup.2 may be substituted with substituents. Furthermore, R.sup.2 may be joined to the heterocyclic ring which is completed by and form a ring. However, at least one of the groups represented by R.sup.1, R.sup.2 and Z contains an alkynyl group, acyl group, hydrazine group or hydrazone group, or alternatively a 6-membered ring is formed with R.sup.1 and R.sup.2 and a dihydropyridinium skeleton is formed. Moreover, at least one of the groups represented by R.sup.1, R.sup.2 and Z may be a group which promotes adsorption on silver halide. Y is a counter ion for balancing the electrical charge, and n is 0 or 1.