Minnesota Mining and Manufacturing Company

Imation Corporation

Robert J Nairne

Ranjan C Patel

Andrew W Mott

Alexis Sarah Zinn-Warner

Sharon Mary Simpson

Doreen Catherine Lynch

Justine A Mooney

Dian E Stevenson

Stephen S Poon

Duncan M Grieve

John H Stibbard

Julian M Wallis

Mark R Chambers

Philip I Mayo

Colin F Norman

Ian T Morgan

David C Bays

Kim Marie Vogel

Kevin D Landgrebe

Roger A Mader

Gilbert L Eian

Raymond J Kenney

Takuzo Ishida

Richard R Ollmann, Jr

Richard J Ellis

Charles G Barlow

Gregory L Zwaldo

William E Bottomley

A L Beck

The invention is a surface modifier for magnetic pigments having the formula:

Surface modification of magnetic particle pigments

A laser addressable thermal imaging element comprising a bleachable photothermal converting dye in association with a heat-sensitive imaging medium, and a photoreducing agent for said dye, said photoreducing agent bleaching said dye on laser address of the element. The imaging element may be in the form of a colorant transfer system, a peel-apart system, a phototackification system or a unimolecular thermal fragmentation system. Also provided is a method of crosslinking a resin by leaser irradiation, which is useful in the production of colored images.

Laser absorbable photobleachable compositions

A black-and-white, negative-acting, silver halide emulsion is described which gives improved image tone when used in a photographic element. The toning agents are based on dithio-substituted compounds having the following general structures: ##STR1## where R.sub.1 and R.sub.2, independently, are selected from the group consisting of alkyl, aryl and heterocyclic groups, or R.sub.1 and R.sub.2 together complete a ring;

Image toners for silver halide photographic films

A silver halide emulsion of average grain size 0.2 .mu.m or less comprising silver halide grains having a core and an outer shell, the core comprising at least 85 mol % of the total silver halide content of the grain and at least 50 mol % of the silver halide in the core being silver bromide, and the outer shell comprising silver halide of which greater than 50 mol % is silver chloride; the emulsion either containing no rhodium dopant, or containing rhodium dopant such that the concentration of said dopant is at least as great in the core as in the shell.

Photographic materials with improved image tone

An imaging method is provided that includes a tetraarylpolymethine dye, and bleaching this dye by bringing the dye into contact with a 4-alkyl or 4-unsubstituted 1,4-dihydropyridine derivative.

Thermal bleaching of infrared dyes

An image-forming element comprising a substrate, and an image-forming medium comprising (a) a compound absorbing at a first wavelength in the UV/blue region and (b) a dye absorbing at a second wavelength which is longer than the first wavelength, irradiation at said second wavelength bleaching absorption of said compound at said first wavelength, said element being free of thermally unstable urea and/or carbamate molecules.

UV-absorbing media bleachable by IR-radiation

Blue-black color favored in medical imaging is imparted to black and white photographic emulsions by the addition of a compound of formula I or II: ##STR1## wherein: R.sup.1 and R.sup.2 independently represent one or more carbon atoms necessary to complete a 5, 6 or 7 membered ring;

Alteration of image tone in black and white photographic materials

A thermographic element comprising in a non-aqueous binder medium a silver salt oxidizing agent in reactive association with a compound comprising a plurality of redox color releasing moieties such that oxidation of each redox color releasing moiety causes release from said compound of a thermally diffusible dye. The compounds many of which are new incorporate two or more developer moieties into a single molecule to minimize the diffusibility of the compound. Following oxidation, either directly by the silver salt or by means of a cross-oxidizing agent, each oxidized developer moiety releases a thermally diffusible dye. The compounds are of sufficient size and molecular weight to slow or prevent diffusion in imaging systems and yet possess several active developer moieties per molecule which is advantageous over known ballasted dye releasers which comprise bulky molecules with only a single developer moiety.

Developing agents for (photo) thermographic systems

A photothermographic element comprising a support bearing at least one heat-developable, photosensitive, image-forming photothermographic emulsion layer comprising:

Hydrazide redox-dye-releasing compounds for photothermographic elements

Positive-acting photothermographic elements suitable for use at contact speeds comprising a base layer having at least two layers thereon, which layers define a photosensitive medium comprising a photocurable composition, a reducible silver source, and a reducing system for silver ion comprising one or more components including a compound capable of reducing silver ion to silver metal, such that the reducible silver source and at least one component of the reducing system for silver ion are present in separate layers, wherein exposure of the element to actinic radiation causes curing of the photocurable composition in the exposed area(s), said curing preventing the reducing system from interacting with the reducible silver source during thermal processing and in which the photocurable composition comprises a free radical curable resin and a photoinitiator therefor having an absorbance to radiation in the wavelength range of 340 to 440 nm, which photoinitiator upon exposure to said actinic radiation or during subsequent thermal processing undergoes a loss of absorption in said wavelength range 340 to 440 nm.

Positive-acting photothermographic materials

Growing community of inventors

Bishops Stortford, United Kingdom

Robert J Nairne