Reproduction of colored images
US4613897A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 8, 1985 |
| Grant date | Sep 23, 1986 |
| Priority date | — |
| Expiry date | Oct 8, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/54
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In color printing, it is customary to analyze the color content of an original using red, blue and green filters and to make color-component printers for the complementary colors, i.e. cyan, magenta, and yellow, with or without a black printer. The present invention concerns the preparation of a special color printer for a printing ink the color of which is not complementary to one of the said filters, for example a brown separation. According to the invention, sets of values (Ybr, Mbr, Cbr) defining the characteristic elements of curves for yellow, magenta and cyan, which curves together correspond to a range of values for the required color separation, are stored. For each picture element, a combination of color-component values for yellow, magenta and cyan (Y, M, C), are derived and are compared with different sets of values (Ybr, Mbr, Cbr) derived from the stored curve elements, each set corresponding to a different value of the required special-color separation (Br). A value is selected for the desired special-color separation for which each of the stored values of the related set (Ybr, Mbr, Cbr) is not greater than the corresponding value (Y, M, C) derived from the picture el…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.