The present invention provides a support for a lithographic printing plate, from which a lithographic printing plate precursor having excellent scratch resistance can be obtained by combining the support with an image recording layer, a lithographic printing plate precursor, and a method of producing a lithographic printing plate. The support for a lithographic printing plate according to the present invention, including an aluminum plate, and an anodized aluminum film disposed on the aluminum plate, in which a plurality of projections are present on a surface of the support for a lithographic printing plate on a side of the anodized film, an average value of equivalent circular diameters of the projections in a cut surface at a position that is 0.5 ?m greater than a position of the projections with an average height is in a range of 3.0 to 10.0 ?m, and a density of the projections with a height of 0.5 ?m or greater from the position of the projections with the average height is in a range of 3,000 to 9,000 pc/mm.sup.2.

Provided is a positive type photosensitive resin composition including: a polymer compound which contains, in a main chain thereof, a sulfonamide group and a structure represented by Formula A-1; and an infrared absorbent. In Formula A-1, X represents NR.sup.1, S, or O, R.sup.1 represents a hydrogen atom or an alkyl group, and each symbol * independently represents a bonding position with respect to another structure.

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Provided are a planographic printing plate precursor, a laminate thereof, and a method of producing a planographic printing plate precursor capable of satisfying all purposes for eliminating interleaving paper used for preventing scraping and peeling, preventing adhesion, imparting a plate-separating property for preventing multiple-plate feeding, and preventing scratches. The planographic printing plate precursor which includes a polymer layer on a surface of a belt-like support 12 includes a back coat layer 70 having an arithmetic average surface roughness Ra of 0.5 m or greater due to a surface roughness structure in which thin film portions 60 and thick film portions 62 are continuously formed on a rear surface of the belt-like support 12.

A stack including: a lithographic printing plate precursor including an image-recording layer which contains an infrared absorber, a polymerizable compound, and a polymerization initiator; and an interleaving paper stacked on the lithographic printing plate precursor, in which air permeation resistance of the interleaving paper is 55 seconds or more, or a stack including: a lithographic printing plate precursor including an image-recording layer which contains an infrared absorber, a polymerizable compound, and a polymerization initiator; and an interleaving paper stacked on the lithographic printing plate precursor, in which the interleaving paper is overlapped with the lithographic printing plate precursor to be in contact with a surface of the lithographic printing plate precursor on an image-recording layer side, and a color difference ?E of the image-recording layer before and after storage in a dark room in an environment of 25? C. and 55% RH for 3 days is less than 3.0.

The present invention provides a printing plate precursor including a layer which includes a polymer and is provided on a printing surface side of an aluminum support, and a layer which includes particles and is provided on a side opposite to the printing surface side, in which a modulus of elasticity of the particles is 0.1 GPa or more, and in a case where a Bekk smoothness of an outermost layer surface on the side opposite to the printing surface side is denoted by b second, a specific expression (1) is satisfied; a printing plate precursor laminate; a method for making a printing plate; and a printing method.

Provided is a printing plate precursor including: a support; a layer which contains a polymer on one side of the support; and a layer which contains a metal oxide obtained by hydrolyzing and polycondensing an organic metal compound or an inorganic metal compound and fine particles on the other side of the support, in which an average particle diameter of the fine particles is 0.3 m or greater and is greater than the thickness of the layer containing a metal oxide and fine particles, and in a case where the printing plate precursors are laminated, dislocation in stacking precursors, adhesion between precursors, and scratches can be all prevented even without using interleaving paper.

A method for manufacturing a lithographic printing plate precursor includes the steps of providing a support as a web, coating an image recording layer on the front side of the support, and depositing a back layer on the back side of the support using a deposition technique which is capable of depositing the back layer according to a predefined image. The method enables stacking and recutting of lithographic printing plate precursors without the need for interleafs.

A method for manufacturing a lithographic printing plate precursor includes the steps of providing a support as a web, coating an image recording layer on the front side of the support, and depositing a back layer on the back side of the support using a deposition technique which is capable of depositing the back layer according to a predefined image. The method enables stacking and recutting of lithographic printing plate precursors without the need for interleafs.

The invention is directed to a lithographic printing plate precursor including, in the following order: a support; an image-recording layer containing a radical polymerizable compound and a radical polymerization initiator; and a protective layer containing a star polymer, and the star polymer is preferably a polymer in which from 3 to 10 polymer chains are branched from a central skeleton.