VERFAHREN ZUR HERSTELLUNG VON TAFELKORNEMULSIONEN

A process is disclosed of preparing silver halide emulsions containing tabular grains bounded by [100] major faces comprised of the steps of (1) introducing silver and halide salts into a dispersing medium and (2) maintaining conditions within the dispersing medium that promote the formation of tabular grains bounded by [100] major faces. The process is characterized in that of the tabular grains bounded by [100] major faces a portion accounting for 50 percent of total grain projected area selected on the criteria of adjacent major face edge ratios of less than 10 and thicknesses of less than 0.3 mu m internally at their nucleation site contain iodide and at least 50 mole percent chloride, at least the selected portion of the tabular grains being formed ty nucleation in a continuous double jet reaction in the presence of iodide with chloride accounting for at least 50 mole percent of the halide present in the dispersing medium and the pC1 of the dispersing medium being maintained in the range of from 0.5 to 3.5. Following nucleation tabular grain growth is undertaken in a reaction vessel which receives emulsion from the continuous double jet reactor until the tabular grains having a thickness of less than 0.3 mu m exhibit achieve a selected average aspect ratio.