Dainippon Ink and Chemicals, Incorporated

Kiyoshi Suematsu

Yasuhiko Kojima

Yasuo Shigemitsu

Naoki Obi

Jun Takeuchi

Haruhiko Kaji

Hiroaki Muratake

Masatoshi Katayama

An image-forming process developing a previously image-exposed silver halide photographic material with an alkaline developer containing a reductone compound as a main developing agent in the presence of a 1,2,5-thiadiazole compound and/or a 2,1,3-benzothiadiazole compound, and the silver halide photographic material and the photographic developer being used for the process are disclosed. In this case, the 1,2,5-thuiadiazole compound and/or the 2,1,3-benzothiadiazole may be contained in the silver halide photographic material and/or the alkaline developer. Super high-contrast images for photomechanical process having a gamma of higher than 15 and having no pepper and less fog can be obtained.

Process of forming super high-contrast negative images and silver halide

A process of forming a super high-contrast negative image is disclosed, which comprises the steps of imagewise exposing a negative-working silver halide photographic material comprising a support having thereon one or more hydrophilic colloidal layers, at least one of the one or more hydrophilic colloidal layers being a negative-working silver halide emulsion layer, and then developing the photographic material with a developer containing an aminophenol derivative developing agent and a reductone compound in the existence of an organic compound having a negative reduction potential. A negative-working silver halide photographic material and a photographic developer being used for the image-forming process are also disclosed.

A direct positive silver halide photographic material and a method for forming a high contrast image using the same are disclosed, in which a pre-fogged direct positive silver halide emulsion layer contains a salt of a nitrogen-containing compound having at least one pyridine nucleus and at least one pyridinium nucleus. The photographic material, after imagewise exposure, is developed with an alkaline developer containing a developing agent, preferably a reductance compound. The photographic material provides high contrast characteristics having a gamma exceeding 10.

Direct positive silver halide photographic material and method for

A silver halide photographic material is disclosed. The photographic material comprises a support having coated thereon one or more hydrophilic colloidal layers, at least one of the hydrophilic colloidal layers being a negative working silver halide emulsion layer, wherein said silver halide emulsion layer or another hydrophilic colloidal layer contains a water-soluble polymer or copolymer having a quaternary ammonium salt in a repeating unit. The process for forming a high contrast negative image using the photographic material is also disclosed.

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Tokyo, Japan

Kiyoshi Suematsu