Eastman-Kodak Company

Ming-Jye Lin

Jong-Shinn Wey

James M Sanders

Michael C Schrader

Michael P Lionti

A process and apparatus for precipitating a silver halide emulsion is disclosed. The process is comprised of the steps of adding silver ions to a dispersing medium containing halide ions within a reaction vessel to initiate growth of silver halide grains within the dispersing medium, monitoring the temperature of the dispersing medium to establish the equilibrium solubility product constant of silver and halide ions within the dispersing medium; concurrently, using a reference electrode and a first indicator electrode, monitoring the halide ion activity within the dispersing medium; and adjusting the level of dissolved halide ion in the reaction vessel to maintain a stoichiometric excess of halide ions, based on the equilibrium solubility product constant. In the process the potential difference between a silver ion specific electrode in contact with the dispersing medium within the reaction vessel and at least one of the first indicator electrode and the reference electrode is concurrently monitored to allow the level of dissolved silver ion to be determined independently of the equilibrium solubility product constant, and the level of dissolved silver ion in the dispersing medium is adjusted based on the potential difference to maintain a selected profile of dissolved silver ion during silver halide grain growth. The apparatus contains the elements necessary for the practice of the process.

Process for independently monitoring the presence of and controlling

Automatic titration method and apparatus provides for adjustment of the electric potential of a solution. A programmed computer responsive to iterative measurements of the potential regulates a two-phase adjustment process which approaches the desired electric potential (overall aim) using sub-aims thereby preventing overshoot of the overall aim.

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Penfield, NY, United States of America

Ming-Jye Lin