Photographic diazotype films comprising fluorescent ultraviolet absorbers

Claim 1

A DIAZOTYPE PHOTOGRAPHIC POSITIVE COPY FILM, COMPRISING (A)A FILM BASE CONSISTING ESSENTIALLY OF CELLULOSE ALKANOATE, (B) A TOP LAYER ON AND SUBSTANTIALLY INTEGRAL WITH SAID FILM BASE WHICH TOP LAYER CONSISTS IN ITS MAJOR PORTION OF PARTIALLY HYDROLYZED CELLULOSE ACETATE AND HAS A THICKNESS OF FROM ABOUT 5 TO 10 MICRONS AND CONTAINS IN FINE DISPERSION THEREIN (1) A CATLONIC LIGHT-SENSITIVE ARYL DIAZONIUM COMPOUND SUITABLE AS DIAZOTYPE DEVELOPABLE COMPONENT, AND (H)AN ANIONIC, CELLULOSE BYDRATE-SUBSTANTIVE, NON-COLOR-IMPARTING GREENISH-BLUE TO VIOLET FLUORESCING COMPOUND SELECTED FROM THE GROUP CONSISTING OF THE SULFONATED STILBENES, SULFONATED DEHYDROTHIOTOLUIDINES, SULFONATED DIPHENYLS AND SULFONATED DIBENZYLS WHICH ARE CAPABLE OF DECREASING THE CONTARST OF THE SAID ARYL DIAZONIUM COMPOUND SUFFICIENTLY TO ADJUST THE PHOTOGRAPHIC GAMMA OF SAID FILM MATERIAL CLOSER TO 1, AND HAVE A MAXIMUM LIGHT-ABSORPTIVITY IN THE ULTRAVIOLET RANGE BETWEEN ABOUT 300 AND 390 MILLIMICRONS.