| 摘要 |
PURPOSE:To maintain the sensitivity of a photosensitive material and to reduce fog by using a specified compound as a blocked photographic reagent contained in a photosensitive silver halide emulsion layer of the photosensitive material. CONSTITUTION:A compound represented by formula VII is used as a blocked photographic reagent contained in a photosensitive silver halide emulsion layer of a photosensitive material. Since the pH of the film is 6-7 during storage, even when a compound represented by formula IV or V is partially formed, a reaction by which the compound returns to the original compound represented by formula I takes place preferentially, so the release of A<-> is inhibited. The release of A<-> is remarkably accelerated under alkali conditions during processing because the equilibrium leans toward a compound represented by formula VI. Accordingly, when A<-> is a photographically useful reagent having a timing group, a reaction by which the timing group is cleaved takes place after a reaction by which the compound represented by the formula VI is formed from the compound represented by the formula I , and the photographically useful reagent is released. Thus, the compound represented by the formula VII has high shelf stability and releases rapidly the photographically useful reagent during processing. In the formulae, A is a photographically useful reagent, each of X<1> and X<2> is carbonyl or the like, Z is a group of atoms required to form a 5- - 7-membered ring, and each of R<1>-R<3> is a substituent.
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