Direct positive silver halide photographic material and method for forming high contrast positive image using the same

摘要

A direct positive silver halide photographic material and a method for forming a high contrast image using the same are disclosed, in which a pre-fogged direct positive silver halide emulsion layer contains a salt of a nitrogen-containing compound having at least one pyridine nucleus and at least one pyridinium nucleus as a partial chemical structure. The photographic material, after imagewise exposure, is developed with an alkaline developer containing a developing agent, preferably a reductone compound. The photographic material provides high contrast characteristics having a gamma exceeding 10.