Preparation of photographing emulsion and device used for the same

PROBLEM TO BE SOLVED: To obtain a method for forming a photographic emulsion which does not form irreversible insoluble chemical species by introducing a silver salt Ag + added to a loop at the point in the loop arranged outside the reaction zone of a range where this silver salt is settled almost completely, introducing an Ag + soln. in the form of a jet disposed at the center in a reactor and specifying the Reynolds number at the introducing point of the Ag + salt. SOLUTION: The silver salt Ag + soln. is circulated in an external circulating loop including a reactor 12 where the soln. is introduced at a point 30 existing upstream of an introducing point 31 of the first halide salt X 1 - . The second soln. of X 1 - is introduced at the point 31 of the loop existing outside the reaction zone R of the range where the Ag + added to form silver halide particles or to grow the particles in the soln. is mostly completely settled. The Ag + soln. is introduced in the form of the jet 'arranged at the center' of the reactor into the reaction 12. The Reynolds number Re at the introducing point 30 of the Ag + salt is so set as to exist between about 5000 and about 50,000. COPYRIGHT: (C)1997,JPO