(57) Process for preparing a photographic emulsion containing tabular silver halide grains, which exhibit high speed upon sensitization, having a thickness of about 0.05 to 0.5 µm, average grain volume of about 0.05 to 1.0 µm³ and mean aspect ratio of greater than 2:1 comprising

A. adding silver nitrate to a vessel containing dispersing medium/bromide mixture, initial bromide ion concentration 0.08 to 0.25 N, to form tabular seed grains;

B. adding an ammoniacal base solution, to achieve 0.002 to 0.2 normal of the base (e.g., after at least 2% of total silver nitrate has been added); and

C. adding additional silver nitrate and halide, i.e., Br⁻ or BrI⁻, by balanced double jet procedure. The emulsions are used in photographic elements for x-ray, graphic arts, etc.