| 摘要 |
1,159,985. Photographic processes. INTERNATIONAL POLAROID CORP. Aug.23, 1966 [Aug.25, 1965], No.37745/66. Heading G2C. [Also in Division C3] A photographic diffusion transfer process comprises the imagewise transfer of imageforming components, as a consequence of development, from an exposed silver halide to an imagereceiving material via a contiguous layer of alkaline processing solution, the solution having pH greater than 11 and containing a polymeric material which is in solution but is precipitated on reduction of pH, and reducing the pH to between 7 and 11 which causes the layer to adhere to the image-receiving material. Alternatively, the alkaline processing solution may act as the imagereceiving material and this layer is solidified after reducing the pH and the solidified layer is left adhering to the silver halide emulsion if the process is performed as set out in Specification 714, 412. Specified polymeric materials are phenol-formaldehyde resins, polyvinyl acetals, polysulphonamides and polyhydroxymethylene. The diffusion transfer process is generally the dye developer transfer process but may be the silver salt diffusion transfer process. In the examples an image-receiving sheet (similar to those Specification 1, 071, 086) comprising a cellulose nitrate support coated with various polymeric layers including a layer of a partial butyl ester of an ethylene/maleic anhydride copolymer (which reduces the alkalinity of the processing solution) is contacted with an exposed silver halide emulsion with an alkaline processing solution containing one of the polymers specified above between the emulsion and the sheet and then separating the image-receiving sheet containing the dye image with the processing layer adhering thereto; its alkalinity having been reduced by the copolymer layer in the image-receiving sheet so that it adhers thereto. Alternatively, the alkalinity may be reduced by adsorption of carbon dioxide from the atmosphere. The adherence of the processing layer enhances the density of the dye image as not all the dye is transferred to the image-receiving sheet. |
