Abstract: A process is disclosed of producing photographically useful radiation sensitive silver halide emulsions the grains of which are of a predetermined size distribution, including selection of maximum and minimum grain diameters and selection of the distribution of grains of maximum, minimum, and intervening diameters. This is achieved by modifying a double jet precipitation to introduce during the run stable silver halide grains capable of acting as host grains for the deposition of additional silver and halide ions. The degree to which the host grains initially introduced are grown determines the maximum grain diameter of the emulsion. The minimum diameter of the grains in the emulsion produced can be determined by the diameter of the stable silver halide grains introduced at the end of the run. The rate at which the stable host grains are introduced during the run controls the distribution of intervening grain sizes.