On-press developable, negative-working lithographic printing plate precursors are used to provide lithographic printing plates. Such precursors are prepared with a substrate and one or more negative-working, infrared radiation-sensitive imagable layers. The substrate is prepared by two separate anodizing processes to provide an inner aluminum oxide layer having an average dry thickness (T.sub.i) of 650-3,000 nm and inner micropores having an average inner micropore diameter (D.sub.i) of <15 nm. A formed outer aluminum oxide layer comprises outer micropores having an average outer micropore diameter (D.sub.o) of 15-30 nm; an average dry thickness (T.sub.o) of 130-650 nm; and a micropore density (C.sub.o) of 500-3,000 micropores/m.sup.2. The ratio of D.sub.o to D.sub.i is greater than 1.1:1, and D.sub.o in nanometers and the outer aluminum oxide layer micropore density (C.sub.o) in micropores/m.sup.2, are further defined by the outer aluminum oxide layer porosity (P.sub.o) as:

0.3P.sub.o0.8

wherein P.sub.o is 3.14(C.sub.o)(D.sub.o.sup.2)/4,000,000.

Provided are a planographic printing plate precursor for furnishing a planographic printing plate in which edge stain does not occur, adhesion to interleaving paper is prevented, and the water width with respect to edge stain at the time of printing is wide; a method of producing the same, and a printing method using the same. The planographic printing plate precursor including: a support; an image recording layer formed on the support; and a water-soluble compound having a molecular weight in a range of 60 to 300 and a solubility of 10 g/L or greater in water at 20 C., in which a content of the compound per unit area in a region on the image recording layer side from an end portion of the planographic printing plate precursor to a portion inside the end portion by 5 mm is greater than a content of the compound per unit area in a second region other than the first region by an amount of 50 mg/m.sup.2 or greater.

Provided are a planographic printing plate precursor for on-press development, including: an aluminum support; an interlayer which contains a compound containing a support absorptive group and a hydrophilic group; and an image recording layer which contains an infrared absorbing agent, a polymerization initiator, a polymerizable compound, and polymer particles formed of a styrene copolymer, on the aluminum support, in which the aluminum support is an aluminum plate having an anodized film on a surface in contact with the interlayer and the anodized film has micropores extending in a depth direction from a surface in contact with the interlayer, and an average pore diameter of the micropores in the surface of the anodized film is in a range of 20 to 40 nm; a method of preparing a planographic printing plate and a planographic printing method obtained by using the planographic printing plate precursor for on-press development.

A planographic printing plate precursor having an image recording layer on a support, and an overcoat layer in this order, in which the overcoat layer includes particles, the overcoat layer is an outermost layer, and an occupation area ratio of the particles in a surface of the overcoat layer is 30% by area or more; and a method of producing a planographic printing plate obtained by using the planographic printing plate precursor.

An on-press development type lithographic printing plate precursor including a support and an image-recording layer on the support, in which the image-recording layer contains a polymerizable compound, a polymerization initiator, and an infrared absorber, and a color forming substance precursor, and a color forming substance generated from the color forming substance precursor has a maximal absorption wavelength in a wavelength range of 380 nm or more and less than 580 nm, at which an absorbance difference with respect to the color forming substance precursor is 0.1 or more, and a maximal absorption wavelength in a wavelength range of 580 nm or more and 750 nm or less, at which an absorbance difference with respect to the color forming substance precursor is 0.07 or more, and a method of preparing lithographic printing plate or a lithographic printing method, using the on-press development type lithographic printing plate precursor.

A color developing composition containing a compound represented by the Formula (1) as defined herein, a lithographic printing plate precursor including a support and an image-recording layer containing the color developing composition, a method for producing a lithographic printing plate including: exposing the lithographic printing plate precursor in an image pattern; and removing a non-exposed portion in the image-recording layer using at least one of printing ink or dampening water on a printer, and a color developing compound represented by the Formula (1) as defined herein.

A planographic printing plate precursor includes: a hydrophilic support; and an image recording layer which contains an organic-inorganic hybrid particle (A) and an infrared-ray absorbent (B) on the hydrophilic support, and the organic-inorganic hybrid particle (A) is an organic-inorganic hybrid particle in which an inorganic particle (a) containing a hydroxyl group and an organic component (b) are linked to each other through a linking group (c) having a urethane bond or a urea bond.

Provided is a planographic printing plate precursor including: a support; and an image recording layer formed on the support, in which the content of fine particles per unit area in a region on a plate surface on the image recording layer side from an end portion of the planographic printing plate precursor to a portion inside the end portion by 5 mm is greater than the content of the fine particles per unit area in a region other than the region by an amount of 10 mg/m.sup.2 or greater, edge stains are not generated therein, and transferring of the image recording layer is prevented even in a case where planographic printing plate precursors are stored in a stacked state. Further, provided are a method of producing the same and a printing method using the same.

An on-press development type lithographic printing plate precursor including a support, and an image-recording layer on the support, in which the image-recording layer contains an infrared absorber, a polymerization initiator, a polymerizable compound, and one or more compounds selected from the group consisting of a compound represented by Formula (1) and a compound represented by Formula (2) (in Formula (1) and (2), Ra.sub.1 and Ra.sub.2 represent an alkyl group, Rb.sub.1 and Rb.sub.3 represent an alkyl group, Rb.sub.2 and Rb.sub.4 represent an alkyl group, and EDG's each independently represent a hydrogen atom or an electron-donating group, provided that at least one of the four EDG's in Formula (1) represents an electron-donating group).

An on-press development type lithographic printing plate precursor includes a support, and an image-recording layer on the support, in which the image-recording layer contains an infrared absorber, a polymerization initiator, a polymerizable compound, and at least one compound selected from the group consisting of a compound represented by Formula (1) and a compound represented by Formula (2) (in Formulae (1) and (2), Ra.sub.1 and Ra.sub.2 represent an alkyl group, Rb.sub.1 and Rb.sub.3 represent an alkyl group, Rb.sub.2 and Rb.sub.4 represent an alkyl group, and EWG's each independently represent a hydrogen atom or an electron-withdrawing group, provided that at least one of the four EWG's in Formula (1) represents an electron-withdrawing group).