| 摘要 |
PROBLEM TO BE SOLVED: To reduce a cost of production of a low silver black-and-white mate rial, particularly a radiographic material prior to sale and environmental load, after the processing of the material after exposure. SOLUTION: In the method for preparing emulsion containing 111} hexagonal tabular grains having an average aspect ratio of >5:1, the tabular grains are formed, while keeping (a) pH in a reactor in the range of 0.8-10.0, (b) the concentration of a gelatinous defloculant at 0-50 g per liter of dispersion medium in the reactor and (c) pBr at a value of at least 1.8 in nucleation. The nucleation is carried out in the reactor at a temperature in the range of 10-60 deg.C, and pBr in the reactor is kept at a value of <2.4 during growth. The growth is carried out in the reactor at a temperature in the range of 40-80 deg.C, and a gelatinous defloculant which does not contain calcium ions and having <30μmol methionine content per gram of gelatinous defloculant is present in the dispersion medium in the nucleation and growth of grains.
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