Agfa Gevaert Nv

Agfa-gevaert

Kris Viaene

Jean-Marie O Dewanckele

David R Terrell

Jan Gilleir

Geert De Roover

Paul R Callant

Hieronymus Andriessen

Etienne A Van Thillo

Ann L Verbeeck

Hartwig Andries

A method has been disclosed for preparing a co-precipitated microcrystalline dye dispersion, the absorption spectrum of which exceeds the summoned spectra of individually dispersed dyes, which comprises, as consecutive preparation steps: adding to one vessel, an amount of at least one pentamethine oxonol-type barbituric acid filter dye having ionizable sites in its molecular structure; adding thereto an aqueous alkaline solution in an amount sufficient to completely dissolve the said filter dye while stirring the solution thus formed; adding in another vessel, to an amount of at least one pyrrole type filter dye, an amount of water, followed by adding of an aqueous alkaline solution and a surfactant; followed, after having completely dissolved (under stirring conditions) the said pyrrole type filter dye, by adding to the solution thus formed in the other vessel, the solution formed in the one vessel; adding an aqueous acidic solution up to a pH of less than 3.0; adding an aqueous alkaline solution up to a pH in the range from 4.0 up to 5.5; followed by adding a binder in order to make the dispersion thus obtained ready-for-coating in a filter dye layer on a support, suitable for use as antihalation undercoat layer between said support and a light-sensitive layer or as a backing layer of said material, or as layer covering the light-sensitive layer, thus providing safelight protection.

Method of preparing co-precipitated microcrystalline dye dispersions and layers coated therewith in materials

A silver halide photographic film element has been disclosed, said element comprising on a light-sensitive side of a transparent polyester support, and, in order, an electrically conductive subbing layer, an antihalation undercoat, a light-sensitive emulsion layer or multilayer arrangement, optionally including one or more intermediate, non-light-sensitive layers between emulsion layers in said multilayer arrangement, and a protective overcoat; and on a backing layer side opposite thereto, in order, a subbing layer containing a lubricant and a topcoat layer, characterized in that on the light-sensitive side of said element said subbing layer comprises an antistatic agent providing a substantially unchanged electrical resistivity of the said element before and after processing of said material, and said antihalation undercoat optionally comprises a high temperature boiling solvent; whereas on the backing layer side a friction coefficient of the backing layer versus stainless steel remains unchanged in the range between 0.20 and 0.30 before and after processing of said material, even after removal of the said topcoat layer during processing in an alkaline developer.

Silver halide photographic material comprising a permanent conductive subbing layer and a scratch-resistant backing layer

A black-and-white silver halide photographic material has been disclosed, coated on a support with at least one light-sensitive emulsion layer, comprising a spectrally sensitized prefogged direct-positive silver halide emulsion, providing peak absorption in the wavelength range from 600 nm up to 700 nm, wherein said emulsion comprises a binder and core-shell emulsion crystals having silver bromide in a total amount of at least 80 mole %, characterized in that said emulsion is spectrally sensitized with a combination of a desensitizing dye having an absorption maximum wavelength in a range from 600 nm up to 700 nm, if present as a sole dye in said emulsion, and at least one azacyanine dye having an absorption maximum at a more hypsochromic wavelength.

Light-sensitive silver halide photographic material for forming direct-positive images and method for making same

A photographic light-sensitive silver halide material is provided for making negative lithographic images or direct-positive images, said material comprising a support, at least one internal latent image-type silver halide emulsion layer (in the case of direct-positive materials) or surface latent image-type silver halide emulsion layer (in the case of lithographic materials) and development-nucleating amounts of a compound or a precursor thereof, said compound having at least one quaternary heterocyclic ring system comprising at least three rings including a tetrahydropyridinium ring wherein carbon-nitrogen and carbon-carbon double bonds are also part of an aromatic ring being one of said three rings and wherein said double bonds and nitrogen atom in said tetrahydropyridinium ring are incorporated into annelated conjugated ring systems. Developing said photographic material after exposure in an alkaline surface developer rapidly converts said precursor into a ring system as defined hereinbefore.

Method for making negative lith images direct positive images

A process is disclosed for the preparation of a hybrid direct positive silver halide emulsion comprising the steps of (1) forming an essentially cubic host grain emulsion consisting of silver bromide or silver iodobromide, with a iodide content between 0 and 10 mole %, by a balanced double jet, (2) depositing epitaxially on the corners of said formed essentially cubic host grains a silver iodide crystallographic phase wherein said silver iodide phase contains at most 5 % of the total crystal silver halide, either by precipitating a silver chloride epitaxial phase and converting it to silver iodide, or by adding silver ions and an organic iodide releaser. The organic iodide releaser is preferably mono-iodoacetic acid.

Process for the preparation of a hybrid direct positive emulsion and

The present invention provides a method for making direct-positive photographic images comprising the steps of image-wise exposing a photographic light-sensitive silver halide material comprising a support and a layer of an internal latent image-type silver halide emulsion the pAg of which has been adjusted to a value of at least 8.5 before coating, and developing said exposed photographic silver halide material in a surface developer in the presence of at least one development nucleator which is not able to react with but which is able to adsorb weakly on the surface of the silver halide emulsion crystals prior to development, but which contains a group protected against reaction with silver halide and which is transformed during development in a nucleating derivative with an enhanced reactivity for the silver halide crystals. Photographic materials comprising these novel development nucleators are also described.

Method for making direct-positive photographic images

The present invention relates to a method for making direct-positive photographic images by developing light-sensitive materials in the presence of development nucleators which do not cause loss of sensitivity during exposure or unevenness of development. More specifically the invention relates to the formation of direct-positive images having a high maximum density and high exposure latitude and to photographic materials for use in said formation, which is accomplished by a method for making direct-positive images comprising:

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Bonheiden, Belgium

Kris Viaene