Abstract: Lithographic printing plates are imaged using an inkjet printer to imagewise apply a chemical or masking agent onto the plate surface. In some embodiments, the chemical causes an affinity change, thereby facilitating lithographic printing.

Abstract: Lithographic printing plates are imaged using an inkjet printer to imagewise apply a chemical or masking agent onto the plate surface. In some embodiments, the chemical inhibits a photoreaction in the top layer.

Abstract: Lithographic printing plates are imaged using an inkjet printer to imagewise apply a chemical or masking agent onto the plate surface. In some embodiments, the chemical causes an affinity change, thereby facilitating lithographic printing.

Abstract: A process for imaging a lithographic printing plate having a coating containing diazo resins. An ink jet printer is used to apply micro drops of a basic chemical solution that insolubilizes the affected areas of the coating to a developing solution. The latent image may be cured by heating the plate for a short period, and is then developed. The process works with conventional, commercially available lithographic plates and developers.

Abstract: A process for imaging a lithographic printing plate having a presensitizing coating. An ink jet printer is used to apply imagewise micro drops of an insolubilizing solution that insolubilizes exposed areas of the coating. The latent image is then developed. The process works with conventional, commercially available developing processors.

Abstract: A process for imaging a lithographic printing plate having a presensitizing coating. An ink jet printer is used to apply imagewise micro drops of an insolubilizing solution that insolubilizes exposed areas of the coating. The latent image is then developed. The process works with conventional, commercially available developing processors.

Abstract: A process for imaging a lithographic printing plate having a coating containing diazo resins. An ink jet printer is used to apply micro drops of a basic chemical solution that insolubilizes the affected areas of the coating to a developing solution. The latent image may be cured by heating the plate for a short period, and is then developed. The process works with conventional, commercially available lithographic plates and developers.

Abstract: A process for imaging a lithographic printing plate having a presensitizing coating. An ink jet printer is used to apply imagewise micro drops of an insolubilizing solution that insolubilizes exposed areas of the coating. The latent image is then developed. The process works with conventional, commercially available developing processors.

Abstract: A process for imaging a lithographic printing plate having a coating containing diazo resins. An ink jet printer is used to apply micro drops of a basic chemical solution that insolubilizes the affected areas of the coating to a developing solution. The latent image may be cured by heating the plate for a short period, and is then developed. The process works with conventional, commercially available lithographic plates and developers.

Abstract: A process for imaging a lithographic printing plate having a coating containing diazo resins. An ink jet printer is used to apply micro drops of a basic chemical solution that insolubilizes the affected areas of the coating to a developing solution. The latent image may be cured by heating the plate for a short period, and is then developed. The process works with conventional, commercially available lithographic plates and developers.

Abstract: A process for imaging a lithographic printing plate having a coating containing diazo resins. An ink jet printer is used to apply micro drops of a basic chemical solution that insolubilizes the affected areas of the coating to a developing solution. The latent image may be cured by heating the plate for a short period, and is then developed. The process works with conventional, commercially available lithographic plates and developers.

Abstract: A water soluble diazonium salt composition made by the condensation of diazoaryl amines and aldehydes and precipitated to form a polymeric anionic species having both ZnCl.sub.4.sup.= and HSO.sub.4.sup.- moieties. These composition are blended with suitable binders, colorants and other optional components to produce light sensitive coating compositions. When applied to aluminum substrates, these light sensitive coating compositions form lithographic printing plates that are especially stable under high humidity conditions. Such plates may be developed by either water alone or by water which contains surfactants and/or a small amount of an organic solvent.

Abstract: This invention relates to a composition and method for enhancing the contrast of images of an underlying photolithographic layer. A photographic element, including a photoresist layer, is applied to a substrate. The photoresist layer contains a contrast-enhancing layer including at least one light-sensitive compound capable of producing acidic photoproducts upon exposure to actinic radiation, at least one indicator dye that changes color on exposure to acidic conditions and at least one polymeric binder soluble in water or weakly alkaline aqueous solutions. The photographic element is exposed to active radiation sufficient to cause photobleaching of the contrast enhancement layer and exposure of the photoresist layer. The photographic element is exposed to actinic radiation sufficient to cause photobleaching of the contrast enhancement layer and exposure of the photoresist layer.

Abstract: This invention relates to a composition and method for enhancing the contrast of images of an underlying photolithographic layer. A photographic element, including a photoresist layer, is applied to a substrate. The photoresist layer contains a contrast-enhancing layer including at least one light-sensitive compound capable of producing acidic photoproducts upon exposure to actinic radiation, at least one indicator dye that changes color on exposure to acidic conditions and at least one polymeric binder soluble in water or weakly alkaline aqueous solutions. The photographic element is exposed to active radiation sufficient to cause photobleaching of the contrast enhancement layer and exposure of the photoresist layer. The photographic element is exposed to actinic radiation sufficient to cause photobleaching of the contrast enhancement layer and exposure of the photoresist layer.

Abstract: An improved aqueous alkaline developer for imagewise-exposed positive-acting photolithographic articles comprising a basic substance wherein the improvement comprises addition of a neutral salt of an alkali metal cation to the developer.

Abstract: Storage stable lithographic printing plates employing novel light sensitive, high molecular weight diazo polymers are herein provided. The novel diazo polymers of the instant invention have the generic formula: ##STR1## Where R is methyl or hydrogenX is methoxy, ethoxy or hydrogenY is oxygen or sulfurZ is an anion of a sulfonic, carboxylic or phosphonic acidn is an integer from 8 to 970.

Abstract: Light sensitive, high molecular weight diazo polymers useful for the manufacture of color proofing guides are herein provided. The novel diazo polymers of the instant invention have the generic formula: ##STR1## Where R is methyl or hydrogen X is methoxy, ethoxy or hydrogenY is oxygen or sulfurZ is an anion of a sulfonic, carboxylic or phosphonic acidN is an integer from 8 to 970.