| 摘要 |
1,242,739. Silver halide direct-positive emulsions. KONISHIROKU PHOTO INDUSTRY CO. Ltd. Dec.23, 1968 [Dec. 23, 1967], No. 61192/68. Heading G2C. A light-sensitive silver halide direct-positive photographic emulsion contains a water-soluble salt or complex salt of rhodium, at least one merocyanine or trimethine cyanine sensitizing dye and at least one magenta, yellow or cyan colour coupler. The compounds are called colour couplers in order to make their chemical structure clear and are not used to form coloured images in this case. Many colour couplers are listed in the Specification. The colour coupler is preferably present in an amount of from 7À5-150g per mole of silver halide. The emulsion preferably contains 10-800 mg of a sensitizing dye for light of long wavelength per mole of silver halide. The rhodium compound is preferably a rhodium halide or a hexahalorhodate. An organic desensitizer may be used in conjunction with the coupler. The organic desensitizer may be pinakryptol yellow, pinakryptol green or phenosofranine. The emulsion is preferably a silver chlorobromoiodide emulsion. The emulsion may also contain stabilizers, hardening agents or matting agents. These emulsions are resistant to fogging and sensitized only in the appropriate wavelength regions. The amount of sensitizing dye, required to attain the same sensitivity as that of conventional light-sensitive silver halide direct-positive photographic emulsions, can be reduced and dye-staining on the white background of the material after development can be prevented. |
