POST-ACTIVATION TYPE DRY IMAGE FORMING MATERIAL INCLUDING AN OXIDIZING AGENT FOR SILVER AND A BROMO COMPOUND AS PHOTO REACTIVE OXIDIZING AGENT

摘要

A post-activation type dry image forming material comprising (I) a silver salt component reducible to free silver upon light exposure and including silver iodide; (II) a redox reactive composition capable of making a visual change by a redox reaction of said composition, said reaction being initiated by heating in the presence of free silver; (III) an oxidizing agent for free silver which has an oxidizing capacity for free silver but is rendered photosensitive by heating and which, upon light exposure after said heating, is suppressed with respect to the oxidizing capacity for free silver and capable of catalytically promoting the redox reaction of said composition; and (IV) a photoreactive oxidizing agent, upon light exposure, capable of returning the reduced oxidizing agent for free silver to the original state. A post-activation type dry image forming material which is extremely excellent in stability of the raw image forming material, that is, can be stored in a light room for a time as long as a period of the order of years and which has high sensitivity can, for the first time, be realized by the ingenious combination of components. The effect of the interaction between the components, especially between the components (I), (III) and (IV) is noticeable in imparting to the present image forming material an extremely high stability of the raw image forming material.