Photographic elements containing ballasted electron-accepting nucleophilic displacement compounds

摘要

Photographic elements, processes for forming images in photographic elements and new compounds are disclosed. Generally, the invention relates to ballasted electron-accepting nucleophilic displacement compounds; after acceptance of at least one electron (reduction) by a nucleophile precursor group, the compounds are capable of undergoing intramolecular nucleophilic displacement to release a diffusible moiety, such as an image dye or a photographic reagent. In certain embodiments, the ballasted electron-accepting nucleophilic displacement compounds are used in combination with electron donors and electron-transfer agents. The processes disclosed are particularly useful in providing positive transfer images using negative-working silver halide emulsions.