Abstract:
Process for removing unexposed diazo from a silicated aluminum lithographic printing plate having a hydrophilic, anionic, negatively charged surface and a layer of a light sensitive, cationic diazo material which has been selectively exposed to actinic light in an image area. The plate is contacted after exposure with a solution of an anionic material in water. Anionic material from the solution ionically couples with unexposed diazo material and the solution still containing anionic material dissolves the coupled product from the unexposed areas producing a clean, hydrophilic background.
Abstract:
Lithographic printing plates are made by exposing to actinic light a lithographic plate having a water soluble light sensitive layer thereon and a coating of a solvent soluble, UV curable material thereover to form an image in the light sensitive layer and adhere said layer to the overlying UV curable material. The plate is developed with water to remove light sensitive layer and overlying UV curable material in the non-image areas, and the plate is exposed to UV source having an intensity greater than the imaging light to form a press-ready plate having a durable, reinforced cured image thereon.
Abstract:
Method for lithographic printing wherein a lithographic printing plate having oleophilic and hydrophilic areas on the printing surface of the plate is contacted with ink and an aqueous fountain solution during printing. An aqueous solution comprising an enzyme is used as the fountain solution.
Abstract:
Aluminum substrate suitable for making lithographic plates which has been treated to render the surface hydrophilic and negatively charged and thereafter ionically colored with a cationic dye.
Abstract:
Planar surfaces are roughened by graining with an aqueous slurry of unfused platy, crystalline alumina. Preferably, an aluminum base with is adapted to receive a light-sensitive coating thereon to make lithographic plate is grained with said aqueous slurry.
Abstract:
An article having an aluminum substrate, an unsealed, porous anodic oxide layer thereon and electrolytically deposited, randomly distributed discrete metal islands having a root portion anchored in one or more pores of the oxide layer. The metal islands extend from the root portion above the surface of the oxide layer in a bulbous, undercut configuration.A process for treating aluminum is also disclosed and includes the steps of electrolytically anodizing aluminum surfaced articles to form an unsealed, porous anodic oxide layer thereon followed by electrolytically depositing randomly distributed discrete metal islands in the pores of the oxide layer and extending above the surface thereof in the bulbous, undercut configuration.