| 摘要 |
PURPOSE:To form prints with high reproducibility to copy by forming two kinds of halftone negatives from the copy while changing the exposing condition, making two kinds of lithographs, and carrying out superposition printing with both the lithographs. CONSTITUTION:By illuminating copy 1 with lamp 2A, the image of copy 1 is thrown on film 5A brought into contact with contact screen 4 through lens 3 by main exposure to form halftone dots of the white side of copy 1 on film 5A. Next, copy 1 is flash exposed with flash 6 to form halftone dots of the black side of copy 1 on film 5A. By this two-stage exposure the 1st negative with the image of the whole density range formed on film 5A is obtd. Main exposure 2B is then carried out with 2-5 times as much light as the light used in the formation of the 1st negative to form the 2nd halftone negative of halftone to black using another film 5B. Plates corresponding to the negatives are made by a photomechanical process, and superposition printing is carried out with an offsetting machine. |
