Mitsubishi Paper Mills Limited

Kazunaka Endo

Eiji Kanada

Shigeyoshi Suzuki

Masahiko Saikawa

Kyonosuke Yamamoto

Akira Tanaka

Motozo Yamano

Kyonosuke Yammamoto

Disclosed is a panchromatic silver halide photographic emulsion for use in DTR process which exhibits a high sensitivity, especially to blue light, a high contrast and a high resolving power and a photographic element containing said silver halide emulsion layer. Said emulsion contains a blue-sensitizing dye represented by the general formula [I]: ##STR1## (wherein Z.sub.1, Z.sub.2, R.sub.1, R.sub.2, X.sub.1 and m are as defined before). Said emulsion may contain, as green- and red-sensitizing dyes, those represented by the general formula [II] and [III] to attain more effectively the objects: ##STR2## (wherein Z.sub.3, Z.sub.4, Z.sub.5, Z.sub.6, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, X.sub.2, X.sub.3 and m are as defined before). Said photographic element is an excellent ligtographic printing plate.

Panchromatic silver halide photographic element

Printing characteristics of a lithographic printing plate material using the silver complex diffusion transfer process and comprising a support and a silver halide emulsion layer and a surface physical development nuclei layer are markedly improved when the emulsion layer comprises two emulsion layers, the lower layer of which has substantially no light-sensitivity.

Lithographic printing plate materials with light insensitive silver

There is disclosed a method for exposing in two steps a photosensitive material to an original of a continuous tone image mingled with a line image through a lens of a process camera of the daylight type, which comprises feeding said photosensitive material to an exposure unit disposed in nearly vertical position in said camera and provided with a suction mechanism, and setting the sensitive material in place; (A) in case of the first step exposure being made to an original of a continuous tone image, (a) moving a contact screen from a position in front of the photosensitive material to establish a close contact with the photosensitive material and exposing the sensitive material imagewise to the continuous tone image, subsequently (b-1) moving the contact screen by the internal shift to the position in front of the sensitive material so that it is out of the exposure region while the sensitive material being remained as such, or (b-2) moving the contact screen internally to a position in front of the sensitive material and then shielding the latter against light in such a manner that the sensitive material can be released of the shield at the time of the second step exposure, the contact screen being absent at least in the exposure region at the time of second step exposure and subsequently (c) exposing the sensitive material to the line image (second step exposure), or (B) in case of the first step exposure being made to the line image, (a') exposing the sensitive material to the line image in the first step, then (b'-1) moving the contact screen, which is in front of the sensitive material and kept outside the exposure region, to establish close contact with the sensitive material while the sensitive material being remained as such, or (b'-2) shielding the sensitive material against light in such a manner that the sensitive material can be released of the shield at the time of bringing the contact screen into close contact with the sensitive material and moving the contact screen from a position in front of the sensitive material to establish a close contact with the photosensitive, and subsequently (c') exposing the sensitive material to the continuous tone image (second step exposure).

Method of exposing photosensitive material

Disclosed is a method for plate-making which comprises imagewise exposing by scanning type flash exposure a lithographic printing plate comprising a support and at least a silver halide emulsion layer containing at least 70 mol % of silver chloride and prepared with addition of a water soluble iridium compound during emulsification or physical ripening of silver halide and a water soluble gold compound at any time before coating of the emulsion and thereafter subjecting the exposed emulsion to diffusion transfer development.

Lithographic printing plate

Disclosed is a method for the direct making of printing plates for multicolor lithography capable of faithfully reproducing repeatedly continuous gradation multicolor original, which comprises using color separation filters for at least blue, green, and, red and repeating a sequence of the steps of shielding an exposure section against light by a light shielding means; feeding to said exposure section a magazine containing a sensitive material convertible into lithographic printing plate, which material bears a panchromatically sensitized photographic layer; bringing said sensitive material into close contact with a contact screen; exposing said sensitive material through a lens and a color separation filter to the reflected light from a continuous gradation multicolor original; and sending the exposed sensitive material to a processing bath section.

Method for direct plate making from multicolor original

Disclosed is a process for making a lithographic printing plate by utilizing the silver complex diffusion transfer process and using a neon-helium laser or an LED which comprises imagewise exposing to the radiation a photosensitive element including an emulsion layer which is spectrally sensitized with an anion- or betaine-type meso-substituted trimethine cyanine dye having at least one .beta.-naphthothiazole nucleus and developing the element by the silver complex diffusion transfer process.

Growing community of inventors

Nagaokakyo, Japan

Kazunaka Endo