Method and apparatus for the conversion of color values

US5835244A · kind A · utility

Assignee

• Linotype-Hell AG · DE

Inventor

• Günter Bestmann · Altenholz, DE

Key dates

• Filing date: Sep 4, 1996
• Grant date: Nov 10, 1998
• Expiry date: Sep 4, 2016

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N1/6033
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A method and an apparatus for the conversion of color values of a first color space into color separation values of a printing color space characteristic of a printing process in apparatus and systems for color image processing. For the purpose of exact adaptation of the color separation values C, M, Y, K! of the printing color space to the respective printing process, the functionally allocated color separation values C, M, Y, K! are first approximately analytically calculated from the color values L*, a*, b*! of the first color space as a printing table C, M, Y, K=f(L*, a*, b*)!, taking the printing colors of the respective printing color space of the later printing process, the colorimetric properties of the printing material employed later, and the printing process parameters into consideration. Subsequently, the calculated printing table C, M, Y, K=f(L*, a*, b*)! is corrected by a color value calibration correction values dL*, da*, db*! are calculated by comparison of the color values L*(v), a*(v), b*(v)! of the first color space characteristic of the colors of a test table to the colorimetrically measured color values L*(m), a*(m), b*(m)! of the corresponding colors of the te…