1. A PRESENSITIZED PRINTING PLATE WHICH COMPRISES A NON-METALLIC SUPPORT HAVING A LIGHT-SENSITIVE LAYER THEREON, THE LATTER COMPRISING A CONDENSATION PRODUCT, CONDENSED IN A STRONGLY ACID MEDIUM, OF A DIPHENYLAMINE-4DIAZONIUM SALT WITH A COMPOUND CONTAINING A REACTIVE CARBONYL GROUP, AND AN EXCESS OF A STRONG ACID SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID, HYDROCHLORIC ACID, HYDROBROMIC ACID, NITRIC ACID, PERCHLORIC ACID, HYDROFLUOBORIC ACID, ALKYL PHOSPHONIC ACIDS, ORGANIC SULFONIC ACIDS, AMIDOSULFONIC ACIDS, SELENIC ACID, ARSENIC ACID, VINYLPHOSPHONIC ACID, AND HEXAFLUOROPHOSPHORIC ACID, IN A QUANTITY OF AT LEAST ONE EQUIVALENT WEIGHT OF ACID PER MOLE OF DIAZONIUM GROUPS.

15. A PROCESS FOR DEVELOPING A PRINTING PLATE WHICH COMPRISES EXPOSING A COATED NON-METALLIC BASE MATERIAL TO LIGHT UNDER A MASTER AND DEVELOPING THE RESULTING IMAGE, THE COATING COMPRISING A CONDENSATION PRODUCT, CONDENSED IN A STRONGLY ACID MEDIUM, OF A DIPHENYLAMINE4-DIAZONIUM SALT WITH A COMPOUND CONTAINING A REACTIVE CARBONYL GROUP, AND AN EXCESS OF A STRONG ACID SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID, HYDROCHLORIC ACID, HYDROBROMIC ACID, NITRIC ACID, PERCHLORIC ACID, HYDROFLUOBORIC ACID, ALKYL PHOSPHONIC ACIDS, ORGANIC SULFONIC ACIDS, AMIDOSULFONIC ACIDS, SELENIC ACID, ARSENIC ACID, VINYLPHOSPHONIC ACID, AND HEXAFLUOROPHOSPHORIC ACID, IN A QUANTITY OF AT LEAST ONE EQUIVALENT WEIGHT OF ACID PER MOLE OF DIAZONIUM GROUPS.