The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 09, 1998
Filed:
Jan. 24, 1997
Thomas B Brust, Webster, NY (US);
Philip J Dale, Rochester, NY (US);
Philip J Zola, Webster, NY (US);
Terrence R O'Toole, Webster, NY (US);
Eastman Kodak Company, Rochester, NY (US);
Abstract
A process is disclosed of preparing a photographic emulsion comprised of high bromide silver halide tabular grains accounting for greater than 90 percent of total grain projected area. The grains exhibit a low level of size dispersity by reason of forming in the presence of a dispersing medium containing a polyalkylene oxide block copolymer surfactant a population of silver halide grain nuclei containing twin planes, the halide content of the grain nuclei consisting essentially of silver bromide, and growing the silver halide grain nuclei containing twin planes to form the tabular silver halide grains. Inadvertent variation in tabular grain sizes and thicknesses from one precipitation to the next are minimized by growing the silver halide grain nuclei at a pH in the range of from 3.0 to 8.0 and in the presence of at least a 0.01M concentration of a partially dissociated acid having a pKa that is within 2.5 units of the pH and that forms a silver salt more soluble than the silver halide incorporated in the grains.