Manufacture of photographic filters

Claim 1

THE PROCESS OF PRODUCING A FILTER IN SITU FOR USE IN CONNECTION WITH PHOTOGRAPHIC AND LIKE PURPOSES COMPRISING THE STEPS OF INSERTING INTO A MOLD FORMING MOUNT PROVIDED WITH A STEPPED INNER SURFACE A FIRST GLASS PLATE, THEN APPLYING A VISCOUS COLORED FILTER LAYER TO THE UPPER SURFACE OF SAID GLASS PLATE IN A QUANTITY CORRESPONDING TO THE FINAL FILTER STRATUM, SUBJECTING SAID LAYER ON SAID FIRST GLASS PLATE TO VIBRATIONS TO THEREBY FREE SAID LAYER FROM AIR BUBBLES, RIPPLES AND LIKE IRREGULARITIES AND TO THEREBY SPREAD SAID LAYER BEYOND THE UPPER SURFACE OF THE FIRST GLASS PLATE FOR CONTACT WITH THE ADJACENT STEP OF SAID INNER MOUNT SURFACE, ADDING TO SAID LAYER A PLASTICIZER SUBSTANCE CAPABLE OF PRODUCING A CLEAR AND SMOOTH OPTICAL FINISH ON SAID LAYER, INSERTING INTO SAID MOUNT A SECOND GLASS PLATE FOR CONTACT WITH SAID SUBSTANCE, TO THEREBY SANDWICH SAID LAYER AND SAID SUBSTANCE BETWEEN SAID GLASS PLATES, EXERTING PRESSURE TO SAID GLASS PLATES AND SAID SUBSTANCES, TO THEREBY FORCE THE LATTER TO SPREAD BEYOND AND ABOVE SAID SECOND GLASS PLATE, AND FINALLY APPLYING HEAT SUFFICIENT TO BOND SAID SECOND GLASS PLATE TO SAID INNER MOUNT SURFACE AND SAID LAYER, THEREBY FORMING A UNITARY ASSEMBLAGE IN WHICH SAID MOUNT FORMS THE MOLD, AS WELL AS THE HOUSING FOR THE FILTER FOR READY USE IN CONNECTION WITH PHOTOGRAPHIC AND LIKE OPTICAL PURPOSES.