Controlling ink migration and physical color gamut discontinuities in digital color printing
US5861896A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 10, 1995 |
| Grant date | Jan 19, 1999 |
| Priority date | — |
| Expiry date | Mar 10, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K2215/0071
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In color graphics printing, incompatible inks, such as true black and color inks, tend to bleed across color field boundaries. Moreover, in four-color systems, there is a discontinuity in the physical color gamut, as distinguished from the logical color gamut, associated with the redundant color. A method is disclosed for alleviating both problems by adjusting image data prior to dithering. The method slightly shifts the logical color indicated in the image data so as to avoid the discontinuity that arises with neutral colors. Preferably, in a four-color printing system, yellow is depleted in the image data, so that after dithering, more dots of blue ink are printed in a given area than would be printed otherwise. For each pixel, the amount of correction is inversely related to the color saturation. The presence of blue ink dots within the substantially black field reduces bleed along the field edges.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.