| 摘要 |
PURPOSE: To enable the exposure latitude to be comparatively enlarged by forming silver bromoiodide grains and then, forming the rest of it by using <=1mol% silver salt and <=1mol% alkali metal iodide, and alkali metal bromide. CONSTITUTION: This photographic emulsion comprises a dispersion medium and a monodispersion of cubic silver bromoiodide grains having a grain diameter of 0.1-0.7μm and it contains 1-7mol% silver iodide, and the silver bromoiodide grains are prepared by mixing a silver salt, especially, silver nitrate, and alkali metal bromide and iodide in the presence of a thioether ripening agent, until 60-90mol% of the silver salt is added, and then, the rest of the silver bromoiodide grains are formed by adding a <=1mol% silver salt and a <=1mol% alkali metal iodide, and alkali metal bromide, and at that time, silver bromoidide grains having no discriminable shells by the X ray diffraction analysis are contained, thus permitting exposure latitude to be enlarged.
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