PURPOSE: To obtain a dispersion of colloidal silver particles used for yellow filter layers having large absorption of blue light and small absorption of green light by mixing an aq. soln. contg. a reducing agent and an aq. silver salt soln. under stirring that accompanies shear rates higher than prescribed values.
CONSTITUTION: Protective colloid such as gelatin is added to an aq. soln. contg. a reducing agent such as dextrin and an aq. soln. of silver nitrate or the like and these are mixed under stirring that accompanies shear rates higher than 1.0×104 (sec-1), whereby a dispersion of colloidal silver particles is obtained. The temp. of the soln. in this case is preferably 20W90°C, more particularly 40W80°C, and the time for mixing is preferably within 30min. A stirrer provided with casing is more desirable for the stirrer. The shear rate of this device is expressed by the formula.
MICHIGAMI KENJI
HAMADA FUMIO
