Photographic compositions and processes

Abstract

Abstract Photographic compositions including a radiation-sensitive complex of a triorganophosphine, e.g. a triarylphosphine, with an organoazide such as an arylazide are radiation-sensitive and can be imagewise exposed to activating rays to yield a species that can react with a dye-forming coupler to form an image dye, e.g. an azo dye. Optionally, such compositions can include a polymeric binder and/or a dye-forming coupler. In another aspect, imageforming compositions are presented which include the organoazide and a precursor to the triorganophosphine, a phosphonium salt for example, that yields triorganophosphine on treatment with base. With such an embodiment, the composition is relatively lightinsensitive prior to alkaline treatment which activates the composition by forming the phosphine-azide complex in situ, and shelf life is desirably extended. When these compositions are present on a support, photographic or image-forming elements are formed. Once the azide-phosphine complex is present in a composition or element of this invention, imagewise exposure to activating rays for the complex and subsequent or concomitant treatment with a dye-forming coupler or the like produces a photographic image in exposed regions, i.e., a negative image of the original exposure. If a leuco compound, dye forming coupler, etc., is present in the composition, then a visible image generally forms on exposure. After production of the image, it can be stabilized by overall heating. In certain cases, heat fixation also produces intensification of a low density or substantially latent photographic image. If desired, positive images can be formed by thermophotographic means. Once the phosphineazide complex is present in the composition, imagewise exposure to heat desensitizes the complex in heated regions and a subsequent overall exposure to activating rays for the complex produces either a visible or an intensifiable photographic image. No heat fixation is required, but image intensification can be accomplished by heat. Lithographic printing surfaces can be prepared when a hydrophilic polymeric azide is used to form the phosphine azide complex or when hydrophilic polymeric couplers are used to form the dye image.

Inventors

• 👤 P Grisdale
• 👤 B Babb

Bibliographic Details