A negative-working infrared radiation-sensitive lithographic printing plate precursor can be imaged and developed on-press to provide a lithographic printing plate. Such precursor has an initiator composition that contains compound A of Structure (I) and one or more compounds collectively as compound B of Structure (II) or Structure (III):

##STR00001##

wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are independently alkyl or alkoxy groups each having 2 to 9 carbon atoms; at least one of R.sub.3 and R.sub.4 is different from R.sub.1 or R.sub.2; the difference of total number of carbon atoms in R.sub.1 and R.sub.2 and the total number of carbon atoms in R.sub.3 and R.sub.4 is 0 to 4; the difference of total number of carbon atoms in R.sub.1 and R.sub.2 and the total number of carbon atoms in R.sub.5 and R.sub.6 is 0 to 4; and X.sub.1, X.sub.2 and X.sub.3 are the same or different anions.

Provided is a planographic printing plate precursor including: a support; and an image recording layer formed on the support, in which a region on the 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 contains a polymer containing a functional group represented by the following Formula (A), and the content of the polymer per unit area in the region is greater than the content of the polymer per unit area in a region other than the above-described region by an amount of 10 mg/m.sup.2 or greater.

—Si(X).sub.m(R.sup.3).sub.n  (A)

A variable lithographic inking system includes a chamber blade system configured to supply ink to an anilox member of an inking system. The inking system includes a soft ink transfer roll and a hard form roll. Ink is transferred from the anilox roll to the form roll by way of the transfer roll, and from the form roll to a reimageable surface layer of an imaging member of a variable data lithographic system. An ink layer free of ink history is uniformly applied onto a surface of the form roll, and subsequently transferred to the reimageable surface layer while avoiding or substantially eliminating image ghosting related to inking non-uniformities.

Provided is a lithographic printing plate precursor having a support and an image-recording layer on the support, in which the image-recording layer has an infrared absorber, a polymerization initiator, a polymerizable compound 1, a polymerizable compound 2, and a polymerizable compound 3, in which a molecular weight of the polymerizable compound 1 is less than 1,000, a weight-average molecular weight of the polymerizable compound 2 is 1,000 or more and 3,000 or less, and a weight-average molecular weight of the polymerizable compound 3 is more than 3,000 and 15,000 or less.

According to aspects of the embodiments, there is provided a method of measuring the amount of fountain solution employed in a digital offset lithography printing system. Fountain solution thickness is measured by using phase shifted monochromic light to produce optical path differences through the fountain solution film. The intensity of the reflected light through the fountain solution film is very sensitive due to the phase shifted light so interference fringes are easier to delineate and fountain solution thickness measurement more reliable.

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##

An apparatus and method for measuring the thickness of fountain solution (FS) in a Digital Architecture for Lithographic Ink (DALI) printing system by transferring the FS to an optical roller with the properties of a lens and measuring the resulting effect on the refraction of an image captured through the lens. The optical roller may comprise a clear or glass cylinder forming a Fresnel lens cylinder having an engineered surface of known surface roughness and wherein the roller is placed adjacent the image member blanket. A heat source is used to evaporate the FS from the blanket for transfer to the optical roller where the FS wets the roller surface to different degrees based on the FS thickness relative to Fresnel ridge depth. Changes to the optical refraction through the lens varies with the FS thickness. An image sensor (e.g., a CCD camera or image analysis system) evaluates the image through the optical roller for FS thickness determination.

Provided is a lithographic printing plate precursor having an aluminum support and an image-recording layer formed on the aluminum support, in which the image-recording layer contains resin particles A that have an ethylenically unsaturated group and a compound B that has an ethylenically unsaturated group other than the resin particles A and has an ethylenically unsaturated bond valence of 1.5 mmol/g or more. Also provided are a method for preparing lithographic printing plate or a lithographic printing method using the lithographic printing plate precursor.

Provided is an on-press development type lithographic printing plate precursor including an aluminum support and an image-recording layer on the aluminum support, in which the image-recording layer contains an infrared absorber, a polymerization initiator, a polymerizable compound, and an addition polymerization-type resin having a hydrophilic structure, a water contact angle on a surface of the aluminum support on a side of the image-recording layer that is determined by an airborne water droplet method is 110° or less, and the polymerizable compound includes a polymerizable compound having 7 or more functional groups. Also provided are a method for preparing a lithographic printing plate and a lithographic printing method using the lithographic printing plate precursor.

A curable composition includes a salt compound having a) an organic anion in which, in Hansen solubility parameter, δd is 16 or more, δp is 16 or more and 32 or less, and δH is 60% or less of δp 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 are also set out.