Abstract: A method of making improved aluminum printing plates comprising graining the aluminum plates, de-smutting them by treating them with nitric acid solution, then rinsing with hot water, acetating the aluminum plates, and silicating the aluminum plates. The plates are then coated with a photoresist, pattern exposed and developed. The printing plates of the invention have improved characteristics; they have excellent adhesion of the resist in image areas, and ink repellency in non-image areas. The developed printing plates have excellent durability without baking.

Abstract: A method of making improved aluminum printing plates comprising graining the aluminum plates, de-smutting them by treating them with nitric acid solution, then rinsing with hot water, acetating the aluminum plates, and silicating the aluminum plates. The plates are then coated with a photoresist, pattern exposed and developed. The printing plates of the invention have improved characteristics; they have excellent adhesion of the resist in image areas, and ink repellency in non-image areas. The developed printing plates have excellent durability without baking.

Abstract: Printing plates having a photoresist layer thereon that can be exposed by a computer controller laser have improved sensitivity and do not require a photomask step. We have found photoresists that include a film forming polymer, an organo azide and a photosensitive dye that absorbs light at the frequency of the patterning laser and converts it to heat energy. The heat energy in turn elevates the temperature of the organo azide above its dissociation temperature, destroying the azide in areas exposed to the light source, and solubilizing those regions. A post pattern exposure flood exposure with ultraviolet light hardens the unexposed resist, improving its resistance to etch solvents.

Abstract: Printing plates having a photoresist layer thereon that can be exposed by a computer controller laser have improved sensitivity and do not require a photomask step. We have found photoresists that include a film forming polymer, an organo azide and a photosensitive dye that absorbs light at the frequency of the patterning laser and converts it to heat energy. The heat energy in turn elevates the temperature of the organo azide above its dissociation temperature, destroying the azide in areas exposed to the light source, and solubilizing those regions.Flood exposure with ultraviolet light hardens the resist and can be performed prior to or after pattern exposure.