Provided are a lithographic printing plate precursor comprising: an image-recording layer on a support, in which the image-recording layer includes a dye compound having a decomposable group that is decomposed by an acid, heat, or both and a structure in which decomposition of the decomposable group opens a ring or desorbs a leaving group and an electron-donating polymerization initiator, a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used, and a color-developing composition including a dye compound having a decomposable group that is decomposed by an acid, heat, or both and a structure in which decomposition of the decomposable group opens a ring or desorbs a leaving group and an electron-donating polymerization initiator.

Provided are a lithographic printing plate precursor having an image-recording layer on a hydrophilic support, in which the image-recording layer contains an infrared absorbing dye that decomposes by exposure to an infrared ray and a color developer that develops color due to the exposure to an infrared ray and a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used.

Provided are a lithographic printing plate precursor having an image-recording layer on a hydrophilic support, in which the image-recording layer includes an organic polymer particle, and the organic polymer particle is a reaction product obtained by at least reacting an aromatic polyvalent isocyanate compound having a structure represented by Formula PO and water, a method for making a lithographic printing plate having excellent printing resistance in the case of using an ultraviolet-curable ink in printing, a new organic polymer particle, and a resin composition including the organic polymer particle.

##STR00001##

A color-forming composition is useful to provide a printout image in an imaged lithographic printing plate precursor. This color-forming composition includes (a) an acid generator; (b) a tetraaryl borate; (c) an acid-sensitive dye precursor; and (d) a compound having the following Structure (I):

##STR00001##

wherein n is 1, 2, 3, or 4; R independently represents a monovalent substituent or the atoms necessary to form a fused ring if n is at least 2, and at least one R substituent is an electron-withdrawing group. The color-forming composition is included within a negative-working radiation-sensitive imageable layer along with a free radically polymerizable component and a radiation absorber such as an infrared radiation absorber.

Provided are a lithographic printing plate precursor having an image-recording layer on a hydrophilic support, in which the image-recording layer includes a polymer particle including an addition polymerization-type resin having a hydrophilic structure and a crosslinking structure, a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used, a polymer particle including an addition polymerization-type resin having a hydrophilic structure and a crosslinking structure, and a composition including the polymer particle.

The imaging sensitivity of negative-working lithographic printing plate precursors is improved by removing ozone from the ambient air surrounding the precursors that can be stored near an imaging means such as a platesetter prior to use. Ozone can be removed using a suitable filter containing activated charcoal or other ozone decomposing means, through which ambient air is filtered before and during the imaging process.

A lithographic printing plate precursor including an image recording layer on a hydrophilic support, in which the image recording layer includes a polymerization initiator, an infrared absorbent, a polymerizable compound, and an acid color former, and the infrared absorbent includes a compound represented by Formula 1, as well as a method of preparing a lithographic printing plate by use of the lithographic printing plate precursor. In Formula 1, at least one of Ar.sub.1 or Ar.sub.2 has a group represented by the following Formula 2.

XFormula 2

X represents a halogen atom, C(O)X.sub.2R.sub.11, C(O)NR.sub.12R.sub.13, OC(O)R.sub.14, CN, SO.sub.2N.sub.15R.sub.16, or a perfluoroalkyl group, X.sub.2 represents a single bond or an oxygen atom, R.sub.11 and R.sub.14 each independently represent an alkyl group or an aryl group, and R.sub.12, R.sub.13, R.sub.15 and R.sub.16 each independently represent a hydrogen atom, an alkyl group, or an aryl group.

##STR00001##

On-press developable, negative-working infrared radiation-sensitive lithographic printing plate precursors have an aluminum-containing substrate having at least inner and outer aluminum oxide layers. A hydrophilic layer is present on the outer aluminum oxide layer at 0.0002-0.1 g/m.sup.2 and contains a phosphorus-containing compound represented by Formula (I) at a coverage of 50-300 mg/m.sup.2. A hydrophilic polymer can also be present at a lower coverage than that of the phosphorus-containing compound. These precursors have an on-press developable, negative-working infrared radiation-sensitive imageable layer having at least a free radically polymerizable component; an initiator composition that provides free radicals upon exposure to imaging infrared radiation; an infrared radiation absorber having an anionic chromophore; and optionally a polymeric binder that is different from all other components. Such precursors can be imaged and on-press developed to provide lithographic printing plates, and they can be readily manufactured using a particular sequence of steps including multiple anodization steps.

Provided are a curable composition including a sail compound having a) an organic anion in which, in Hansen, solubility parameter, d is 16 or more, p is 16 or more and 32 or less, and H is 60% or less of p and b) a counter cation, a lithographic printing plate precursor having an image-recording layer containing the curable composition, a method for producing a lithographic printing plate using the lithographic printing plate precursor, and a compound that is used in the image-recording layer in the lithographic printing plate precursor.

A planographic printing plate precursor includes: a support; and an image recording layer which includes a radical initiator, a radical polymerizable component, and a radiation absorption compound, and in which the image recording layer shows two or more peaks of a radical generation amount in a radical generation amount-versus-time curve after exposure to image forming radiation, in which the radical initiator includes an electron-donating radical initiator and an electron-accepting radical initiator, and the radiation absorption compound comprises a compound represented by the following Formula 1.

##STR00001##