Method of screening half-tone picture themes

US4557596A · kind A · utility

Assignee

• GAO Gesellschaft für Automation und organisation mbH · DE

Inventors

• Hans E. Muller · Saratoga, US
• Stefan May · Herbertshausen, DE

Key dates

• Filing date: Mar 30, 1983
• Grant date: Dec 10, 1985
• Expiry date: Mar 30, 2003

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S283/901
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A method of screening half-tone picture themes, in which the gray tones of the half-tone picture theme are reproduced by changes in the structural width of a basic screen structure having any desired form. The assignment of a gray tone area of the half-tone picture theme to the screen structure width reproducing this gray tone area may be selectively determined. In a photographic version of the inventive method (FIG. 1), a basic screen structure 1 of any form is prepared and used to produce broadening screen structures as negative films 9,11. The same number of tone separations 20,22 is produced as negative films from the picture theme 13 to be screened, each of which tone separations reproduces a certain gray tone area of the half-tone picture theme which can be adjusted by the exposure time. Tone separations 22,20 are consecutively exposed onto a line material 24 with the broadening screen structures 9,11 respectively assigned to them, the line material then reproducing the screened picture theme in such a way that the gray tone parts determined by the tone separation are reproduced locally by the screen structure width assigned to it. There are several photographic and EDP/scann…