| 摘要 |
PURPOSE:To manufacture a fine-grained photographic emulsion with high single dispersibility, high sensitivity and high contrast in a short time by mixing an aqueous soln. contg. ammonium ions, halide and a hydrophilic colloidal with an aqueous soln. of ammoniacal silver nitrate and an aqueous soln. of acidic halide by a simultaneous mixing method at 8.0-9.0pH to form silver halide crystals and to regulate the grain size of the crystals to 0.15-0.30mum. CONSTITUTION:A liq. mixture prepared by said simultaneous mixing method is kept at a high silver ion concn., so it is important to controll the pH value. When the pH value is increased, the internal sensitivity and internal fog are increased, and the surface sensitivity is reduced. The pH value is adjusted during the formation of silver halide crystals so that it converges on a desired range while keeping the silver ion concn. high. Silver halide crystals are formed at 8.0-9.0pH during mixing, and the grain size of the formed crystals is regulated to 0.15-0.30mum. A photographic silver halide emulsion with high sensitivity and high contrast can be obtd. using the silver halide crystals having 0.15-0.30mum grain size. |
