Agfa-gevaert

Luc Vissers

Herman J Uytterhoeven

Yvan K Gilliams

Luc Bastiaens

Chris Van Roost

A preparation process for a first aqueous dispersion comprising an ex-situ photosensitive silver halide and a substantially light-insensitive silver salt of an organic carboxylic acid, comprising the steps of: separately preparing a second aqueous dispersion comprising the ex-situ photosensitive silver halide and a third aqueous dispersion comprising the substantially light-insensitive silver salt of an organic carboxylic acid; and mixing the second aqueous dispersion with the third aqueous dispersion to produce a mixture thereof, characterized in that the first aqueous dispersion thereby produced is substantially free of a water-soluble metal or ammonium salt of an aliphatic carboxylic acid with greater than 12 carbon atoms and the process further comprises a step selected from the group consisting of: increasing the pH of the second aqueous dispersion to a value of at least 8.0 prior to mixing with the third aqueous dispersion; increasing the pH of the third aqueous dispersion to a value of at least 8.0 prior to mixing with the second aqueous dispersion; and increasing the pH of the mixture to a value of at least 8.0; the first aqueous dispersion obtainable therewith; and the use thereof in preparing a photo-addressable thermally developable element of a photothermographic material. A preparation process for a fourth aqueous dispersion is also provided.

Aqueous dispersion comprising photosensitive silver halide and a substantially light-insensitive silver salt of an organic carboxylic acid

A process for preparing monosheet black and white photothermographic recording material, the photothermographic recording material being exclusive of a dye-providing compound and comprising a support and a photo-addressable thermally developable element, the photo-addressable thermally developable element being thermally developable under substantially water-free conditions and consisting of one or more layers, the layers together comprising photosensitive silver halide, a substantially light-insensitive organic silver salt, a reducing agent therefor in thermal working relationship therewith and a binder, comprising the steps of: (i) coating at least one of the one or more layers of the photo-addressable thermally developable from an aqueous medium; (ii) drying the layer or layers coated in step (i); and (iii) heating the photothermographic recording material at a temperature of at least 35&deg; C. in the dark for a period of at least 3 days; and a photothermographic recording material obtainable therewith.

Photothermographic recording materials with improved stability

A production process for a photothermographic recording material thermally developable under substantially water-free conditions comprising the steps of: (i) providing a support; (ii) producing one or more aqueous dispersions or solutions containing together a substantially light-insensitive organic silver salt, photosensitive ex-situ silver halide in catalytic association with the substantially light-insensitive organic silver salt, a reducing agent in thermal working relationship with the substantially light-insensitive organic silver salt and a binder; (iii) coating the one or more aqueous dispersions or solutions onto the support to form layers which upon drying become a photo-addressable thermally developable element; and (iv) drying the layers, wherein the photo-addressable thermally developable element contains between 0.2 and 2.5 moles of in-situ photosensitive silver iodide per mole of ex-situ photosensitive silver halide produced by reacting particles of the substantially light-insensitive organic silver salt in an aqueous dispersion with a source of iodide ion; and a recording process therefor.

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Brecht, Belgium

Luc Vissers