| 摘要 |
1,221,686. Photographic materials and process. ITEK CORP. Feb.28, 1968 [March 19, 1967], No. 9630/68. Heading G2C. Photographic images are prepared by exposing a photo-catalyst and contacting it before or after exposure with a leucophthalocyanine which is thus converted to the corresponding phthalocyanine dye. The photo-catalyst is reversibly actuated by exposure (so that it is capable of darkening aqueous AgNO 3 solution) but remains essentially chemically unchanged by such exposure. The images may be prepared by a single imagewise exposure or by a short uniform exposure followed by an imagewise exposure using radiation of a different wavelength. They may be fixed by dissolving out the remaining leucophthalocyanine. Alternatively residual leucophthalocyanine in the unexposed areas may be transferred to a solvent impregnated receptor sheet containing a photo-sensitive material (e.g. similar to that in the imaging composition), and the sheet developed by a reducing agent, heat or exposure. Suitable photo-catalysts are metal oxides, sulphides and selenide, potassium aluminium silicate, Ba TiO 3 , gallium nitride, lead molybdate, Pb CrO 4 , photo-chromic and fluorescent materials, organic photo-conductors, and phospho-tungstic, -silicic and -molybdic acids. Preferably, the photo-catalyst is dispersed in a binder and development is effected in the presence of an acid, which may be produced by photolysis of CBr 4 , a boroxine, an α-haloketone, an alkylphosphonic halide or o-nitrobenzaldehyde. |
