Back to results
US 5,362,470 AGranted
Ultrafine gold and/or silver chalcogenide and production thereof
AssigneeKonica Corporation
InventorsHaruhiko Masutomi, Naoko Uchida, Hirofumi Ohtani, Kazuyoshi Ichikawa
Life of this patent
Estimating the term…
Abstract
A method for manufacturing an ultrafine gold and/or silver chalcogenide being used for the sensitivity speck seeding sensitization method is disclosed. The gold and/or silver compound, and a water-soluble chalcogenide are mixed into a protective colloid solution under prescribed condition. The light-sensitive photographic material obtained by this method has a high sensitivity and low fog property.
Claims6
A method of producing a chalcogenide of at least one of gold and silver comprising the steps of:
- (a) preparing a first solution of at least one water soluble compound selected from the group consisting of silver nitrate, chloroauric acid, and gold dimethylrhodanine, and a mixture of chloroauric acid, and a second aqueous solution of a compound selected from the group consisting of hydrogen sulfide, alkali sulfide, thiourea, substituted thiourea, polysulfides, selenoureas and dithiacarbaminic acids;
- (b) simultaneously injecting the first and second solutions into a third protective colloid solution and rapidly mixing the first, second and third solutions, wherein the mixing is effected to produce a chalcogenide product having an average particle size of not more than 60 .ANG. and a coefficient of variation of less than 0.16;
- and
- (c) recovering particles of the resulting chalcogenide product.
1 more element
Dependencies are inferred from the claim text.