HEAT DEVELOPABLE PHOTOGRAPHIC ELEMENT

摘要

PURPOSE:To stop development at a proper time without reducing the attainable density of an image by incorporating a base precursor and a photographic reagent capable of releasing a specified compound by the action of a base into a photosensitive layer and/or an image receiving layer. CONSTITUTION:A base precursor and a photographic reagent capable of releasing a compound represented by formula 1 (where Y is a group of atoms required to form a 5-, 6- or 9-membered heterocyclic ring) by the action of a base are incorporated into a photosensitive layer and/or an image receiving layer. The N-contg. heterocyclic compound having a mercapto group represented by the formula 1 has a development retarding effect in a photosensitive silver halide material. It is preferable that the base precursor causes a certain reaction by heating and releases a base, and the precursor may be the salt of an org. acid and a base causing decarbonation and decomposition by heating or a compound which is decomposed by a reaction such as intramolecular nucleophilic substitution or Lossen rearrangement and releases amine. The base precursor is effective when used by 0.01-40wt% of the amount of a coated film.