Eastman-kodak Company

Sucheta Tandon

Robert James Perry

Kenneth James Lushington

Carl A Marrese

Benjamin T Chen

Jess B Hendricks, Iii

Michael G Antoniades

Lynda W McGarry

Heinz E Stapelfeldt

Donald Robert Irwin

Katrin I Parsiegla

Douglas E Singer

Harold G Judd

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 composition for developing a silver halide color photographic material comprising a color developing agent and a hydroxylamine compound represented by Formula I or II: ##STR1## wherein Stab is a stabilizing group such that when the hydroxylamine compound is added to a test developer solution of the following formula the pH of the test developer solution decreases less than 0.12 at an aeration time of 90 hours:

Color developer containing hydroxylamine antioxidants

Certain 2,1-benzisoxazol-3(1H)-ones are useful as antioxidants in photographic color developer compositions. These compounds are highly water soluble and are essentially odorless. In addition, they have extended shelf life. They are useful in processing silver halide color photographic elements having at least one incorporated dye forming coupler.

Use of 2,1-benzisoxazol-3(1H)-ones as antioxidants in color photographic

A method for controlling pressure-induced fog in a silver bromide photographic material involves surface treatment of the emulsion AgBr grains with thiocyanate and an iodide salt. In particular, a process for making a pressure fog-resistant photographic emulsion includes steps of forming a photographic emulsion containing cubic or cubooctahedral silver bromide grains, surface-treating the AgBr grains with a thiocyanate by adding the thiocyanate to the emulsion, chemically sensitizing the emulsion, maintaining the emulsion at a temperature and for a time sufficient to allow the thiocyanate to react with the grain surfaces, and then surface-treating the AgBr grains with an iodide salt by adding the salt to the emulsion in an amount and under conditions effective to fill in cubic faces of the AgBr grains. The latter step partially or fully converts the AgBr grains to octahedral grains. A photographic element can then be made by coating the emulsion on a suitable base.

Pressure fog-resistant photographic element

Process for making a pressure fog-resistant photographic element

Growing community of inventors

Fairport, NY, United States of America

Sucheta Tandon