| 摘要 |
PURPOSE:To obtain a negative type silver halide photographic sensitive material superior in liquid state long term storage stability and resistance to harmful gases and high in sensitivity and superior in the relationship between sensitivity and fog by forming silver halide grains having an iodide content in an middle shell higher by >=3mol% than in the outermost shell, and the iodide content in the highest content shell higher than in the middle shell by >=3mol%. CONSTITUTION:Photosensitivity is enhanced by forming the middle shell having a middle iodide content between the highest iodide content shell and the outermost surface shell having a lower content. It is preferred to set the iodide content of the highest content shell to 6-40mol% and to a content higher than that of the surface shell by >=6mol%, and when its content is below 6mol%, sensitivity is deteriorated, and when above 40mol%, silver halide grains are turned into a multidispersion state, and so, it is preferred not to exceed 40mol% from the point of sensitivity and sharpness, and to regulate the difference in the content between the the middle shell and the surface shell and the middle shell and the highest content shell to >=3mol%, respectively, and if it is too small, the effect of the middle shell is lessened. The combination of these core-shell type silver halide grains with a magenta coupler enhances stability, etc., of the emulsion contg. this coupler represented by formula I in which Z is a nonmetallic atomic group necessary to form an optionally substd. N-contg. hetero ring; X is a group to be released by the reaction with the oxidation product of a color developing agent; and R is H or a substituent.
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