| 摘要 |
PROBLEM TO BE SOLVED: To readily obtain an organic silver dispersion that gives thermally developable photosensitive material that has excellent storage stability of the images by adding silver nitrate to an aqueous dispersion in which fine particles of an alkali salt of an organic acid are dispersed and removing an alkali nitrate as a by-product by means of a precision filtration membrane. SOLUTION: After silver nitrate is added to an aqueous dispersion of fine particles of an alkali salt of an organic acid (preferably behenic or stearic acid) salt, an alkali nitrate as a by-product is removed by means of a precision filtration membrane. When the silver nitrate is added, particles of a silver halide may be admixed in the aqueous dispersion. For example, in a stock solution tank 1, after the silver nitrate is added to the aqueous dispersion, this dispersion is fed to a filtration unit 8 provided with a ceramic precision filtration membrane with a diaphragm pump 6 to remove the alkali nitrate together with the filtrated water. Further, pure water is added to the stock solution tank 1 in an amount of the same volume as that of the filtrated water, and this operation is repeated.
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