The CIE L*a*b* color space turns tristimulus values into three coordinates spaced so that equal distances look roughly equally different. L* runs from 0 for black to 100 for white, a* is positive toward red and negative toward green, and b* is positive toward yellow and negative toward blue. Mills specify shade as target L*a*b* values with tolerances and follow whites mainly through L* and b*.
CIELAB target is L 95.5, a plus 0.8, b minus 4.2, and we're holding everything but b.
Also heard as
- L*a*b*
- Lab
- CIE Lab
Related terms
b*
Yellow-blue coordinate in CIELAB, positive toward yellow and negative toward blue, watched closely on white papers.
Delta E
Single number for the total color difference between a sample and its target, usually in CIELAB units.
Shade
The exact color of a paper grade measured against its approved standard, for whites as well as tinted sheets.
Standard observer
CIE model of average human color vision, defined for a 2-degree or a 10-degree field of view.