| 摘要 |
PURPOSE:To enhance contrast and max. density, to remarkably sensitize a silver halide emulsion, and to prevent fog in the light and defects of desensitization by incorporating a specified amt. of silver chloride and a desensitizing agent. CONSTITUTION:A negative emulsion, such as silver chloride, chlorobromide, chloroiodide, or chlorobromoiodide, contg. at least 70mol%, preferably, 80mol% silver chloride is used as an emulsion, and its average grain diameter is, e.g., 100-400nm. At least 90% of the number of the total grains are, preferably, contained in the range of + or -10% of the average grain diameter. The desensitizer to be added in this emulsion is organic and positive in the sum of both the anode and cathode potentials of a polarograph, and it is added in an amt. not exceeding the inherent sensitivity of the emulsion logE=1.3, and in the case of a silver chloride emulsion, logE=1.0, and an amt. necessary for decreasing sensitivity. As a result, since the obtained emulsion is high in sensitivity, exposure time can be shortened or illuminance can be lowered, thus permitting rationalization, such as saving of power and shortening of operation length of time. |
