Printing a true-ink reference, and refining gray accuracy, for optimum color calibration in incremental printing
US7027182B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 31, 2000 |
| Grant date | Apr 11, 2006 |
| Priority date | — |
| Expiry date | May 14, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/6033
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Ramps are printed with ink of a particular color, and also nominally in that color but by inks of other colors. A measured actual-ink ramp is a standard to fix the other-colors ramp, and correct other printing in those colors. In one aspect a particular color is gray, actual ink black (K), and other-color inks magenta (M), yellow (Y) and cyan (C). In another aspect, actual ink is red (R), green (G) or blue (B); other colors M, Y and C in respective pairs. For gray/black, the K ramp is a zero-chroma standard to lower composite-black (cK) chroma below ˜2.5 ΔE. A sampling aspect prints for each gray tone plural cK-ink combinations preferably bracketing nominal gray values; and searches these for one nearest the particular gray—or most closely bracketing it, for interpolation—for best match. Bracketing is best optimized, by a color-space pattern centered on nominal. Other aspects are taught.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.