Method of making a graded photo-printing master

Abstract

Abstract A GRADED DOT PHOTO-PRINTING MASTER IS MADE BY PROVIDING A FIRST MASTER COMPRISING A MULTIPLICITY OF SPACED OPAQUE DOTS OF UNIFORM SIZE LOCATED IN A DESIRED PATTERN OR ARRAY ON A CLEAR BACKGROUND; CONTACT PRINTING THE FIRST MASTER TO PRODUCE A SECOND MASTER COMPRISING NEGATIVE REPLICA THEREOF HAVING SPACED CLEAR AREA OF THE SAME SIZE AS THE DOTS ON AN OPAQUE BACKGROUND; AND CONTACT PRINTING THE SECOND MASTER THROUGH A ROTATING SHUTTER HAVING A SPECIALLY-SHAPED APERTRUE FOR VARYING THE TIME OF EXPOSURE FROM A MAXIMUM AT THE CENTER TO A MINIMUM AT THE OUTER EDGE, TO PRODUCE A THIRD MASTER HAVING SPACED CLEAR OR OPAQUE AREAS OF GRADED SIZE ON AN OPAQUE OR CLEAR BACKGROUND, DEPENDING ON THE TYPE OF PHOTOGRAPHIC EMULSION USED. WHEN A POSITIVE TYPE EMULSION IS USED, TO PRODUCE A THIRD MASTER WITH GRADED CLEAR AREAS ON AN OPAQUE BACKGROUND, THAT STENCIL IS SUBSEQUENTLY CONTACT PRINTED WITH A NEGATIVE-TYPE EMUL- SION TO PRODUCE THE FINAL GRADED DOT MASTER WITH SPACED OPAQUE DOTS VARYING IN SIZE FROM A MAXIMUM AT THE CENTER TO A MINIMUM AT THE OUTER EDGE. THIS FINAL MASTER IS USED, WITH ANOTHER MASTER HAVING A SIMILAR PATTERN OF UNIFORML LARGE-SIZE OPAQUE DOTS, TO FORM TH HOLES IN A GRADED MASK FOR A COLOR PICTURE TUBE.

Inventors

• 👤 John A Dodd Jr
• 👤 Robert A Geshner

Bibliographic Details