| 摘要 |
PURPOSE:To rapidly excess of water soluble salts and to facilitate redissolution of silver halide, by using a polymer having specified sulfonic acids or their salts to settle a silver halide emulsion maturated physically. CONSTITUTION:The settling agent to be used is a monopolymer or a copolymer, with styrene or the like, of 1000-100,000 molecular weight and 0.05-0.50 viscosity containing 5 or more, preferably, 50 or more mole% repeating units of the formula (M being H, alkali metal, or NH4 and n being 1-3) in the polymer. The polymer is added to a silver halide emulsion after physical maturation in an amount of 10wt% or more, preferably, 20-50wt% based on gelatin, and rapid settling occurs on adjusting to 2.5-5.0 in pH by citric acid or the like. Salt removal is finished by decantation of the supernatant solution, but when necessary, the precipitation is washed with water, or redissolved and repeated by the above treatments. The precipitate thus obtained is easily redissolvable and, when needed, undergoes chemical maturation. |
