| 摘要 |
<p>This invention relates to a composition and process for enhancing silver images, and, more particularly, for enhancing photographically produced silver images for use in lithography.
<??>In the silver salt diffusion transfer process, an imagewise exposed silver halide emulsion layer is positioned in intimate contact with a receptor element and developed with a silver halide developing composition in the presence of a solvent for silver halide such that the unexposed silver halide is dissolved and subsequently diffuses into the receptor element. Development nuclei, or catalyst, contained in the receptor element, cause the diffusing silver halide to be reduced (i.e., developed) to metallic silver, thereby forming an image on the surface of the receptor element.
<??>One shortcoming of the silver diffusion transfer process is that a substantial level of silver halide is required to provide a positive silver image of sufficient oleophilicity to function as a lithographic plate. Another shortcoming is that there is often insufficent oleophilic/hydrophilic differential between the image areas and background areas of the lithographic plate.
<??>This invention involves a composition for enhancing silver images comprising an oxidizing agent for metallic silver and a silver ion insolubilizing agent which react with photographically produced silver deposits. The composition is particularly useful in enhancing the lithographic utility of photographically produced silver deposits which function as the inkable image area of lithographic printing plates. </p> |
