To bring a silver salt solution and a halide solution into a uniform chemical reaction and to achieve uniform nucleation and growth of silver halide.
A circulation system 86 for drawing a solution in a reaction tank 76 to the outside and feeding the solution in such a way that it is returned to the tank 76 through a mixer 74 is attached to the tank 76 for preparing a silver halide emulsion and silver halide grains generated by introducing a silver salt solution and a halide solution into a microreactor 72 for nucleation and reacting silver ions and halogen ions are fed to the mixer 74 and mixed with the solution in the mixer 74. Water or a protective colloidal aqueous solution in which nuclei as microcrystals of silver halide generated in the microreactor 72 have been dispersed is rapidly mixed by the mixer 74 into an aqueous solution of a dispersion medium in the tank 76. Thus the nuclei of silver halide having the required shape and size formed by the nucleation reaction are fed into the tank 76 in such a way that they are uniformly dispersed.
NAGASAWA EIJI
SHIRAISHI FUMIKO
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