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:
Jul. 30, 1991
Filed:
Nov. 30, 1989
William A Houle, Kimberton, PA (US);
Thomas P Tufano, Hockessin, DE (US);
E. I. Du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
Process for stabilizing the crystalline grain morphology of silver halide grain cores prepared in the presence of a dispersing medium and an aminoazapyridine compound at a pH of 2.5 to 9 and pCl of 0 to 3, at least 50% of the total projected area of the total grain population being noncubic silver halide grain cores and the halide content being at least 50 mole percent chloride, based on total moles of silver precipitated, the improvement wherein after 60% of aqueous silver salt solution based on the total moles of silver precipitated is introduced a second halide salt, e.g., bromide, is added thereby forming on the grain cores a shell of 0.5 to 20 mole % based on the total moles of silver precipitated. The emulsions are useful in X-ray, color separation, inverse transfer films, and 'dry-silver' applications, etc.