Flow control system for the precipitation of silver halide emulsions

DETAILED DESCRIPTION The apparatus includes a first valve assembly for introducing silver salt into the precipitation vessel, a second valve assembly for introducing a halide salt into the precipitation vessel, a flow programmer for generating a time varying flow control signal for controlling said second valve assembly, a set point programmer for generating a set point, a sensor in said precipitation vessel for generating a signal representative of silver ion concentration therein, linearizing means for linearizing the output of said sensor, comparator means coupled to said linearizing means and to said set point programmer for generating a first error signal, ratio means responsive to said flow control signal for modifying said flow control signal by a factor, and adder means responsive to said first error signal and to said modified flow control signal for providing a second flow control signal for controlling said first valve assembly.