Eastman-kodak Company

Melvin D Sterman

Pranab Bagchi

Jacob I Cohen

Dennis E Smith

Wayne A Bowman

Alfred B Fant

Glenn T Pearce

James Lee Bello

Melvin M Kestner

Gary W Visconte

Marianne Yarmey

Gary Francis Mitchell

Howard M Low

Stephen J Kozak

The invention is generally accomplished by providing a photographic element and a process of its formation wherein a gelatin silver halide emulsion is provided with a thickener comprising a copolymer of the structure wherein

Thickener for delivery of photographic emulsions

Methods and compositions are provided for hardening with fast-acting hardeners the colloidal carrier materials, such as gelatin, in the layers of photographic materials, such as photographic film. The methods of the invention comprise coating, with a conventional coating technique, among the layers of a photographic material a layer of a composition of the invention. The compositions of the invention are aqueous solutions which comprise a fast-acting hardener and a polymeric thickener, have concentrations of thickener less than about 50 mg/cm.sup.3 and, at 40.degree. C. and shear rates between about 1000 sec.sup.-1 and 10,000 sec.sup.-1, have viscosities from about 5 cp to about 20 cp and power law indices greater than about 0.90.

Method for hardening photographic materials

The invention provides a method of nucleating silver halide particles wherein said nucleation is carried out in the presence of acid processed ossein (APO) gelatin or chain-extended acid processed ossein (CE-APO) gelatin and the composition formed therefrom.

Use of acid processed ossein gelatin and chain-extended acid processed

Use of acid processed ossein gelatin and chain-extened acid processed

This invention describes the advantages associated with the use of chain-extended acid processed ossein gelatin as the makeup gelatin, with emulsion precipitated in lime-processed ossein gelatin. Such photographic elements show a definite speed-fog advantage, compared to systems where standard lime-processed ossein gelatin is used solely.

Use of chain-extended acid processed ossein gelatin in the preparation

Photographic elements having at least one layer containing polymeric matte particles covalently bonded to gelatin and colloidal silica.

Photographic light-sensitive elements

Photographic elements containing at least one layer containing polymeric particles surrounded by a layer of colloidal inorganic particles and separate particles of colloidal silica.

A soluble, chain extended gelatin having a high molecular weight and significantly higher viscosity at equivalent gelatin concentration compared to standard gelatin and significantly faster setting time is produced by preparing an aqueous gelatin composition containing from about 6% to about 18% dry weight of gelatin and from about 0.25 to about 5 millimoles of a bis-(vinyl sulfonyl) compound per 100 grams of gelatin, heating the composition at a temperature of from about 40 to about 60.degree.C. and at a pH of from about 4.5 to about 7 for from about one to about eight hours.

Chain extended gelatin

A photographic element comprising a support having thereon a gelatin-containing layer, and a matting agent comprising polymer particles covalently bonded to the gelatin in the layer. The polymer particles may be individually covered with gelatin that is covalently bonded thereto and the gelatin that is covalently bonded to the particles may be cross-linked with the gelatin in the layer. There is also provided a process of preparing a photographic element comprising a matting agent and a layer comprising gelatin. In this process, the gelatin layer is coated onto a support, at least partially dried, and polymer particles are applied to the layer. The polymer particles are then covalently bonded to the gelatin in the layer.

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Pittsford, NY, United States of America

Melvin D Sterman