| 摘要 |
PURPOSE:To enable the long-term preservation of a fogged photosensitive silver halide material for a direct positive, to reduce a change in the sensitivity at high temp. and humidity, and to obtain a high contrast image by adding a salt of a specified base to an emulsion layer or other hydrophilic colloidal layer of the material. CONSTITUTION:A photosensitive material for a direct positive is obtd. by adding a compound represented by the formula (where each of R1-R4 is aryl or aralkyl, the group may have a substituent such as halogen, alkyl or NO2, Z is N, P, As or Sb, and X<-> is an anion) to >=1 layer among silver halide emulsion layers and other hydrophilic colloidal layers by 0.001-50g per 1 mole silver halide. The photosensitive material gives a higher contrast than a conventional material, can be preserved over a long term, and has increased stability at high temp. and humidity. |
