Eastman-kodak Company

Dirk J Hasberg

Rajesh Vinodrai Mehta

Ramesh Jagannathan

Chaofeng Zou

Ralph W Jones, Jr

Michael Bryan

Lloyd A Lobo

Kui Chen-Ho

Doreen Catherine Lynch

Jeffrey S Baugher

James E Novak

A process for the preparation of a radiation-sensitive silver halide emulsion comprised of high bromide cubical silver halide grains, the process comprising: (a) providing in a stirred reaction vessel a dispersing medium and high bromide silver halide grain cores, the grain cores comprising at least 5 mole % of the final emulsion silver and the contents of the vessel being maintained at a temperature of at least about 65&#xb0; C., and (b) precipitating a high bromide silver halide shell which comprises at least 5 mole % of the final emulsion silver onto the grain cores by introducing at least a silver salt solution into the dispersing medium at a specified high rate, wherein a minor percentage of chloride ions, relative to bromide, is introduced into the reaction vessel prior to or concurrent with precipitation of the high bromide shell, and wherein the concentration of silver halide grains in the reaction vessel at the end of the precipitation of the shell is at least 0.5 mole/L. The invention provides an improved manufacturing process for the preparation of high bromide silver halide cubical grain emulsion enabling concentrated emulsion batches to be prepared with desired photographic properties.

Process for the preparation of high bromide cubical grain emulsions

Thermally developable materials such as thermographic and photothermographic materials include a co-precipitate comprising first and second organic silver salts, the first organic silver salt comprising a silver salt of a nitrogen-containing heterocyclic compound containing an imino group, and the second organic silver salt comprising a silver salt of a mercaptotriazole. The first organic silver salt can be used in the imaging process as a source of reducible silver ions, and the second organic silver salt can be a source of a toning agent. The co-precipitate can be prepared using double-jet precipitation techniques to provide an aqueous dispersion that can be used in imaging formulations.

Silver salt-toner co-precipitates and imaging materials

Thermally developable materials such as thermographic and photothermographic materials include a novel non-photosensitive source of reducible silver ions that are predominantly provided as rod-shaped particles of silver salt of a nitrogen-containing heterocyclic compound containing an imino group. The rod-shaped particles have an average aspect ratio of at least 3:1 and a width index for particle diameter of 1.25 or less, and provide improved imaging properties. These particles can be prepared using double jet precipitation procedures in which vAg is kept constant at a value of equal to or greater than &#x2212;50 mV.

Thermally developable materials containing organic silver salts with rod-like morphology and method of making and using

Process for the preparation of high bromide cubic grain emulsions

A process for preparing a concentrated photographic spectral sensitizing dye-water composition which comprises adding an anionic sensitizing dye to an aqueous medium in the substantial absence of organic solvent, and agitating the combined dye and aqueous medium, wherein the anionic dye forms a liquid-crystalline dye phase in the aqueous medium and the agitation is performed in the presence of a nonionic surfactant having an HLB of less than 12 and an aqueous solubility at 25&deg; C. of greater than 10 ppm, which nonionic surfactant is in the aqueous medium at a level of from 10 to 1000 ppm. In a specific embodiment of the invention, where the viscosity (at 0.1 s shear rate) of the dye-water composition in the absence of the nonionic surfactant would be greater than 100 cp and especially where such viscosity would be greater than 500 cp, the surfactant is preferably present at a level sufficient to substantially reduce air entrainment during agitation of the dye-water composition.

Process for the preparation of concentrated dye-water compositions

Process for the preparation of high bromide tabular grain emulsions

An apparatus and method for mixing at least two reactants is taught wherein a first reactant is delivered to a reaction zone through a first annular flow path and a second reactant is delivered to the reaction zone through a second annular flow path. The first and second annular flow paths are concentric with one another and the two reactants intermix with one another in the reaction zone. There is a rotating disc having a surface, defining one boundary of the reaction zone. The flow of the first and second reactants across the rotating disc and through the reaction zone is generally radial and has a residence time in the reaction zone of not more than about 100 msec, and preferably not more than about 50 msec. The reaction zone resides in a main reactor vessel and there is a driven agitator residing in the main reactor vessel to stir the contents thereof.

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Rochester, NY, United States of America

Dirk J Hasberg