| 摘要 |
The method of making, and article of manufacture therefor, of a photographic master wherein an unexposed sheet of orthochromatic film is secured to a rotatable drum, moving the drum longitudinally during rotation, and permitting a narrow light source to be exposed to the film resulting in a sheet of film having a series of extremely close parallel lines, and developing the film. The method of making, and article of manufacture therefor, of a halftone screen wherein an unexposed sheet of orthochromatic film is placed adjacent a photographic master, exposing the master onto the film, removing and replacing the master so that the lines of the master are at 90 DEG to the first position, exposing again the film, and developing the film. The method of making and article of manufacture therefor of a halftone screen wherein an unexposed sheet of orthochromatic plate is placed adjacent a photographic master, exposing the master onto the plate, developing the plate, repeating the procedure to a second plate, placing the two exposed plates adjacent with the lines at 90 DEG .
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