the invention concerns a method and a device for preparing a photographic emulsion . the device according to the invention comprises a plurality of external circulation loops disposed in parallel and in which the content of a vessel containing at least a stirred gelatin solution is circulated , the loops having an identical configuration , means being provided for adding in an identical manner , to each of the loops , reagents required for the formation and / or growth of silver halide grains , the output of the circulation loops being recycled continuously in the vessel .