| 摘要 |
PURPOSE:To improve the area rate of blackened parts and to reproduce boundary parts between picture parts and nonpicture parts smoothly by making white lines in one direction different in width from white lines in the other direction on a screen for photogravure. CONSTITUTION:The width of segments 8 of a segment pattern in one direction is made narrower than that of segments 7 in the other direction on the screen for photogravure. When a photogravure printing plate is made by using the screen, parts corresponding to thick white lines 7 of the screen for photogravure are banks 9 and parts corresponding to thin white lines 8 are left as projecting parts 10 only at intersection parts of the banks 9 while the other parts are eliminated by side etching. Therefore, when screen lines nearly as many as usual are secured, the area rate of blackened parts is increased and when the area rate of blackened parts nearly as great as usual is secured, the number of screen lines is increased. Further, boundary parts between picture parts and nonpicture parts are reproduced smoothly. |
