Method of adding hydrophobic images to the hydrophilic surface of positive or negative paper offset plates

Claim 1

A PROCESS OF FORMING AN OFFSET PRINTING PLATE COMPRISING COATING A BASE WITH A COPOLYMER OF VINYL METHYL ETHER AND MALEIC ANHYDRIDE TO FORM A FIRST LAYER OF THE COPOLYMER ON SAID HERE, COATING SAID COPOLYMER LAYER WITH A COMPOSITION COMPRISING A MIXTURE OF AN ALKALI RESISTANT RESIN AND A LIGHT-SENSITIVE DIAZO TO FORM A SECOND LAYER, EXPOSING THE THUS FORMED PLATE TO LIGHT UNDER A PATTERN, REMOVING THE MIXTURE FROM THE EXPOSED PORTIONS OF SAID SECOND LAYER BY TREATMENT WITH A POLYHYDROXY COMPOUND TO THEREBY FORM A HYDROPHOBIC GREASE RESISTANT IMAGE OF THE PATTERN ON THE PLATE, TREATING THE PLATE WITH AN ALKYLOLAMINE TO HYDROLYZE THE PORTION OF THE SURFACE OF THE COPOLYMER OF SAID FIRST LAYER FROM WHICH THE MIXTURE WAS REMOVED, THEREBY RENDERING SAID PORTIONS HYDROPHILIC, RINSING THE THUS FORMED PLATE WITH WATER TO REMOVE PROCESSING LIQUIDS, DRYING THE PLATE AND MANUALLY FORMING A SECOND IMAGE ON SAID HYDROPHILIC PORTIONS BY APPLYING THERETO AN INK COMPRISING AN ALKALI SOLUBLE HYDROPHOBIC POLYVINYL COMPOUND, AN ALKALI AND A VOLATILE ORGANIC SOLVENT.