Abstract: The present invention provides methods of forming and using thermally imageable composite elements which may be developed into lithographic printing plates. More specifically, the present invention provides a method of forming thermally imageable composite elements which provide substantial developer resistance in desired regions, while maintaining white light desensitivity and durability.

Abstract: A method of characterizing a color imaging system is provided. The method comprises obtaining first data indicative of output of the color imaging system. The first data is processed, to yield second data, according to a color appearance model that varies in accordance with neutrality of colors indicated by the first data. Other methods are provided as well as systems and computer program products for characterizing color imaging systems and devices and for producing colors.

Abstract: Methods for making an imaged custom-color overlay. The method includes a) providing a photosensitive ink of a selected color; b) providing a carrier sheet comprising a transparent support sheet and an ink-receiving layer; c) custom-coating the ink-receiving layer with a layer of the ink; d) drying the ink; e) imagewise exposing; and f) developing. The invention permits an end user of a proofing system to make an imaged overlay in a multitude of custom colors on an as-needed basis, without being limited to those colors that are provided by a manufacturer. The methods are suitable to make custom-color overlays using both analog and digital processes. The photosensitive ink may be water-based. Methods for making an overlay proof including an imaged custom-color overlay are also disclosed. The end user of a proofing system may therefore make highly accurate overlay proofs suitable as contract proofs.

Abstract: The invention is directed to compensating for imaging aberrations that result from repeated passes by an imaging laser array. The aberrations may result from swath lines formed by thermal heating and from the ruling and screen angle of the image. The techniques described herein reduce the undesirable aberrations in thermal laser generated images by breaking up and/or reducing the swath lines. In general, the techniques provide for overlapping swaths and providing masking for one or both passes that print the overlapped region.

Abstract: Modeling spectral characteristics of an image acquisition device. In one implementation, a computer system predicts the spectral reflectance or transmittance of a sample scanned by an image acquisition device, such as a graphic art scanner, by modeling the device. The sample is scanned by a scanner. The computer system searches for media coordinates in a colorant space corresponding to the sample. The media coordinates correspond to an estimated spectrum in a basis spectra model. The basis spectra model is derived by analyzing training color patches of the sample distributed throughout the gamut of the colorant set on the sample media. The estimated spectrum generates estimated digital values through a forward model of the scanner. The estimated digital values are compared to target digital values generated by the scanner to calculate an error value. The computer system repeats this process until a desired stopping criterion or criteria are met.

Abstract: Modeling spectral characteristics of an image acquisition device. In one implementation, a computer system predicts the spectral reflectance or transmittance of a sample scanned by an image acquisition device, such as a graphics arts scanner, by modeling the device. The sample is scanned by a scanner. The computer system searches for media coordinates in a colorant space corresponding to the sample. The media coordinates correspond to an estimated spectrum in a media model. The estimated spectrum generates estimated digital values through a forward model of the scanner. The estimated digital values are compared to target digital values generated by the scanner to calculate an error value. The computer system repeats this process until a desired stopping criterion or criteria are met. The estimated spectrum corresponding to the final estimated digital values represents the reflectance spectrum of the sample as scanned by the scanner.

Abstract: A positive working printing form precursor comprises a thermally imagable composition which includes a hydroxyl group-containing polymer, for example a novolak resin. The composition has a weight of less than 1.1 gm−2. It has been found that using a low weight of the composition on the precursor improves the properties of the precursor, in particular by rendering the sensitivity of the precursor to imaging radiation less variable over time.

Abstract: An improved hydrophilized substrate for planographic printing is disclosed. The substrate contains a support and a hydrophilic layer over the support. The hydrophilic layer contains titanium dioxide (titania) particles. In one embodiment, the hydrophilic layer contains a mixture of coated and uncoated titanium dioxide particles, and, optionally, alumina particles. A method for preparation of the substrate and a printing member comprising the substrate are also disclosed.

Abstract: A holder for preventing the incidental rotation of film material on a roll, comprising at least two parts which fit together, with a roll of film material on a roll core therein, having a lip of which extends outside the holder, and a flange having a support plate and a protruding part, which protruding part engages with the roll core, and the anti-incidental rotation mechanism undetachably mounted on the flange.

Abstract: An infrared imaging composition contains two essential components, namely an infrared absorbing compound, and a phenolic resin that is either mixed or reacted with an o-diazonaphthoquinone derivative. These compositions are useful in positive-working elements such as lithographic printing plates that can be adapted to direct-to-plate imaging procedures. The weight ratio of infrared radiation absorbing compound to diazonaphthoquinone moiety is less than 1:14.

Abstract: An assemblage for forming a lithographic printing plate is disclosed. The assemblage contains a receiver support with a rough hydrophilic surface; a layer containing a poly(cyanoacrylate) binder; and a donor support. When the assemblage is exposed with a high intensity laser beam, the binder is transferred to the hydrophilic surface of the receiver support to produce a lithographic printing plate. The transfer requires relatively low exposure and no post processing is necessary.

Abstract: An alkaline developing composition for processing a lithographic printing plate includes an alkali metal silicate and at least 6 weight % of a thickener such as glycerine. The lithographic printing plate can be either positive- or negative-working, and includes negative-working thermal plates.

Abstract: Improved lithographic printing plates adapted to be imagewise-exposed with ultraviolet- or visible-light-emitting lasers such as argon-ion lasers and frequency doubled Nd:YAG lasers, are comprised of a radiation-sensitive layer and an oxygen barrier layer. The radiation-sensitive layer includes one or more addition-polymerizable ethylenically-unsaturated compounds and a photopolymerization initiator system comprised of a spectral sensitizer that sensitizes in the ultraviolet or visible regions of the spectrum and an N-aryl, O-aryl or S-aryl polycarboxylic acid co-initiator; the oxygen barrier layer comprises fully hydrolyzed polyvinyl alcohol; and a basic compound is incorporated in the oxygen barrier layer or the radiation-sensitive layer or both in an amount sufficient to control thermal fog susceptibility of the lithographic printing plate.