Method for generating a screened gray proof having gray values from a color image

US5845056A · kind A · utility

Assignee

• Linotype-Hell AG · DE

Inventors

• Thomas Kohler · Neuenstadt am Kocher, DE
• Klaus Lang · Munster, DE
• Andreas Netthorn · Frankfurt, DE

Key dates

• Filing date: Jan 9, 1997
• Grant date: Dec 1, 1998
• Expiry date: Jan 9, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N1/40012
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A method and apparatus are provided for producing a rastered gray composite proof in which the color values of the chromatic printing inks "cyan", "magenta" and "yellow" are united to brightness-equivalent gray scale values for simple advance monitoring of a color printing. The gray scale values to be printed on the gray composite proof are corrected compared to the gray scale values of the chromatic printing inks for the color printing represented by the color separation values, being corrected to different percentage parts that respectively correspond to the subjectively sensed brightness impression of the chromatic printing inks relative to "black". The color separation values of the chromatic printing inks are converted into individual bit maps by different raster functions such that the recorded pixels of the chromatic printing inks lie next to one another on the recording material. The individual bit maps of the chromatic printing inks are united to form an overall bit map by an OR operation. The control bits of the overall bit map control a black-and-white printer that prints the gray composite proof on the recording material pixel-by-pixel, whereby the control bits of the o…