Abstract: An improved two printing step process for reproducing visual subject matter including the making of a secondary printing plate with a positive image random pattern screen and printing a substrate sequentially and in registry with the secondary printing plate and a master printing plate made with a conventional half tone screen. The random pattern screen is a positive image phototransparency having a large plurality of irregularly shaped highlight areas and constrasting shadow areas per square inch, an optical density from about 0.17 to about 1.6, a contrast factor from about 0.75 to about 1.5 and a transparency factor from about 0.25 to about 0.60. The random pattern screen is made from a transparent plate having light disruptive projections on its surface. A negative and a positive phototransparency of the transparent plate are made while controlling exposure and developing conditions to produce a positive image screen having the desired characteristics.
Type:
Grant
Filed:
February 16, 1977
Date of Patent:
April 17, 1979
Assignee:
Rapoport Printing Corporation
Inventors:
Sidney L. Rapoport, Douglas F. Mitchell
Abstract: Method for substantially improving the shadow detail and color spectrum range of multicolored lithographic reproductions including the preparation of and printing with standard halftone printing plates and overprinting with a secondary printing plate made from a color separation used in making the halftone printing plates; the secondary printing plate being made from a secondary image exposed through a random pattern screen.
Type:
Grant
Filed:
June 2, 1976
Date of Patent:
July 26, 1977
Assignee:
Rapoport Printing Corporation
Inventors:
Sidney L. Rapoport, Douglas F. Mitchell
Abstract: An improved two printing step process for reproducing visual subject matter including the making of a secondary printing plate with a positive image random pattern screen and printing a substrate sequentially and in registry with the secondary printing plate and a master printing plate made with a conventional half tone screen. The random pattern screen is a positive image phototransparency having a large plurality of irregularly shaped highlight areas and contrasting shadow areas per square inch, an optical density from about 0.17 to about 1.6, a contrast factor from about 0.75 to about 1.5 and a transparency factor from about 0.25 to about 0.60. The random pattern screen is made from a transparent plate having light disruptive projections on its surface. A negative and a positive phototransparency of the transparent plate are made while controlling exposure and developing conditions to produce a positive image screen having the desired characteristics.
Type:
Grant
Filed:
October 2, 1974
Date of Patent:
March 8, 1977
Assignee:
Rapoport Printing Corporation
Inventors:
Sidney L. Rapoport, Douglas F. Mitchell