Thermally developable diazotype photoprinting material and production thereof

Claim 1

A DIAZOTYPE PHOTOPRINTING PROCESS WHICH COMPRISES PROVIDING A TWO-COMPONENT DIAZOTYPE PHOTOPRINTING MATERIAL ADAPTED FOR EXPOSURE AND THERMAL DEVELOPMENT INCLUDING A VAPOR PERMEABLE BASE SELECTED FROM THE GROUP CONSISTING OF PAPER AND CLOTH, AN AZO DYE COUPLING COMPONENT ON ONE SIDE OF SAID BASE, A LIGHT-SENSITIVE DIAZO COMPOUND CAPABLE OF COUPLING WITH SAID COUPLING COMPONENT ON THE SAME SIDE OF SAID BASE AS SAID COUPLING COMPONENT, AND ON THE REVERSE SIDE A COMPOUND WHICH PRODUCES ALKALINE VAPORS WHEN HEATED TO TEMPERATURES UP TO 400*F., SAID BASE PROVIDING A BARRIER BETWEEN SAID DIAZO AND COUPLING COMPOUNDS AND SAID VAPOR PRODUCING COMPOUND; EXPOSING SAID FIRST NAMED SIDE TO LIGHT UNDER THE DESIGN TO BE REPRODUCED; AND APPLYING HEAT TO SAID REVERSE SIDE TO PRODUCE SAID ALKALINE VAPORS WHEREBY AN IMAGE OF THE DESIGN DEVELOPS ON THE FIRST NAMED SIDE OF SAID BASE.