Eastman-Kodak Company

Harold G Judd

Seshadri Jagannathan

Kenneth Joseph Reed

Samuel Chen

Allen K Tsaur

David E Fenton

Benjamin T Chen

Jess B Hendricks, Iii

Michael G Antoniades

Sucheta Tandon

Heinz E Stapelfeldt

Donald Robert Irwin

Katrin I Parsiegla

Douglas E Singer

A mixer for preparing silver halide grains for photographic use has upper and lower impellers housed in a draft tube. The bottom impeller has flat blades for micromixing silver and halide reactants introduced into the bottom of the draft tube. The upper impeller has pitched blades for macromixing the bulk fluid. The impellers are spaced apart at least the distance of their diameters so that the upper and lower impellers operate independently of one another so that micromixing is independent of macromixing. A flow disrupter structurally associated with the draft tube and positioned above the top impeller prevents vortexing of the fluid during mixing. Baffles may be provided in the draft tube to discourage vortexing.

Scalable impeller apparatus for preparing silver halide grains

A process of preparing a photographic emulsion having radiation-sensitive silver iodohalide grains. Iodide is introduced into the grains by releasing iodide ions from iodate (IO.sub.3.sup.-). Release of iodide ions from the IO.sub.3.sup.- is employed to enhance the uniformity of iodide availability during emulsion preparation, either during grain precipitation or subsequent halide conversion. The process of the invention is in one preferred form directed to the partial halide conversion of tabular grains. A speed-granularity advantage is demonstrated.

Process for the preparation of silver halide emulsions having iodide

Growing community of inventors

Bolingbrook, IL, United States of America

Harold G Judd