Photographic printing plate

Claim 1

A METHOD OF MAKING AN INTAGLIO PRINTING PLATE WHICH COMPRISES PREPARING A SUPPORT HAVING ON ONE SURFACE A RELATIVELY HEAVY BASE COATING OF PHOTOSENSITIZABLE, SUBSTANTIALLY WATER INSOLUBLE, WATER-SORPTIVE HYDROPHILIC COLLOIDAL SELECTED FROM THE GROUP OF MATERIALS CONSISTING OF PROTEINS, PIGMENTED PROTEINS ,POLYVINYL ALCOHOLS AND MIXTURES THEREOF BONDED TO SAID SUPPORT, A RELATIVELY THIN INTERMEDIATE COATING ADHERING TO SAID BASE COATING AND COMPRISING WATER-SOLUBLE, PHOTOSENSITIZABLE CARBOXY METHYL CELLULOSE AND ARABIN COMPOSITION, AND A TOP COATING COMPRISING A WATER-SOLUBLE, PHOTOSENSITIZABLE, HYDROPHILIC COLLOIDAL SELECTED FROM THE GROUP OF MATERIALS CONSISTING OF PROTEINS, PIGMENTED PROTEINS, POLYVINYL ALCOHOLS AND MIXTURES THEREOF ADHERING TO SAID INTERMEDIATE COATING, PHOTOSENSITIZING THE TOP, INTERMEDIATE BASE AND COATINGS, EXPOSINNG IMAGE-DEFINING AREAS OF THE PHOTOSENSITIZED COATINGS SO AS TO PRODUCE WATER-INSOLUBLE, GREASE-RECEPTIVE PRINTING AREAS AND WATER-SOLUBLE, GREASE-REPELLENT, NONPRINTING AREAS, APPLING TO THE SURFACE OF SAID TOP COATING A FILM OF GREASY MATERIAL, SUBJECTING THE COATINGS TO AN AQUEOUS TREATMENT EFFECTIVE TO WASH OFF THE GREASY MATERIAL FROM SAID NON-PRINTING AREAS, TOGETHER WITH THE UNDERLYING WATER-SOLUBLE TOP AND INTERMEDIATE COATINGS, AND SUBJECTING THE COATINGS TO A FURTHER AQUEOUS TREATMENT TO EFFECT SWELLING OF THE UNEXPOSED AREAS OF TH BASE COATING TO A LEVEL ABOVE THE PRINTING AREAS OF THE TOP COATING.

Claim 2

A METHOD OF MAKING AN INTAGLIO PRINTING PLATE WHICH COMPRISES PREPARING A SUPPORT HAVING ON ONE SURFACE A RELATIVELY HEAVY BASE COATING OF PHOTOSENSITIZABLE, SUBSTANTIALLY WATER INSOLUBLE, WATER-SORPTIVE HYDROPHILIC COLLOIDAL SELECTED FROM THE GROUP OF MATERIALS CONSISTING OF PROTEINS, PIGMENTED PROTEINS ,POLYVINYL ALCOHOLS AND MIXTURES THEREOF BONDED TO SAID SUPPORT, A RELATIVELY THIN INTERMEDIATE COATING ADHERING TO SAID BASE COATING AND COMPRISING WATER-SOLUBLE, PHOTOSENSITIZABLE CARBOXY METHYL CELLULOSE AND ARABIN COMPOSITION, AND A TOP COATING COMPRISING A WATER-SOLUBLE, PHOTOSENSITIZABLE, HYDROPHILIC COLLOIDAL SELECTED FROM THE GROUP OF MATERIALS CONSISTING OF PROTEINS, PIGMENTED PROTEINS, POLYVINYL ALCOHOLS AND MIXTURES THEREOF ADHERING TO SAID INTERMEDIATE COATING, PHOTOSENSITIZING THE TOP, INTERMEDIATE BASE AND COATINGS, EXPOSINNG IMAGE-DEFINING AREAS OF THE PHOTOSENSITIZED COATINGS SO AS TO PRODUCE WATER-INSOLUBLE, GREASE-RECEPTIVE PRINTING AREAS AND WATER-SOLUBLE, GREASE-REPELLENT, NONPRINTING AREAS, APPLING TO THE SURFACE OF SAID TOP COATING A FILM OF GREASY MATERIAL, SUBJECTING THE COATINGS TO AN AQUEOUS TREATMENT EFFECTIVE TO WASH OFF THE GREASY MATERIAL FROM SAID NON-PRINTING AREAS, TOGETHER WITH THE UNDERLYING WATER-SOLUBLE TOP AND INTERMEDIATE COATINGS, AND SUBJECTING THE COATINGS TO A FURTHER AQUEOUS TREATMENT TO EFFECT SWELLING OF THE UNEXPOSED AREAS OF TH BASE COATING TO A LEVEL ABOVE THE PRINTING AREAS OF THE TOP COATING.