Abstract: A copper clad metal printing plate can be coated with an azide-containing photoresist comprising a polyformal resin together with a modified polyformal resin that has up to 100% of its hydroxyl groups converted to carboxyl groups, an organo azide and a photosensitive dye that absorbs light at the frequency of a patterning laser and converts it to heat energy. This de-crosslinks the resin that has been exposed to the laser light. Preferably the photoresist is flood exposed with ultraviolet light prior to laser exposure. The photoresist becomes soluble in the laser-exposed areas, exposing the underlying copper after development. The printing plates are completed by etching away the copper in the exposed areas, removing the remaining photoresist, thereby providing a patterned copper layer on the printing plate.

Abstract: A copper clad metal printing plate can be coated with an azide-containing photoresist comprising a polyformal resin together with a modified polyformal resin that has up to 100% of its hydroxyl groups converted to carboxyl groups, an organo azide and a photosensitive dye that absorbs light at the frequency of a patterning laser and converts it to heat energy. This de-crosslinks the resin that has been exposed to the laser light. Preferably the photoresist is flood exposed with ultraviolet light prior to laser exposure. The photoresist becomes soluble in the laser-exposed areas, exposing the underlying copper after development. The printing plates are completed by etching away the copper in the exposed areas, removing the remaining photoresist, thereby providing a patterned copper layer on the printing plate.