Figure 3

Color conveys a multifaceted message. Not only does it help us identify what we are looking at, but it also evokes feelings. Small wonder we find ourselves describing color by using such terms as “warm red” or “boring gray.” These descriptions sometimes work in casual conversation, but they are vague and mean different things to different people. In the business of color, we need to communicate the colors we see or desire with precision and objectivity. To meet this need, color science pioneers developed several systems to convey a three-dimensional description of color.

As shown in Figure 3, the widely used CIELab* system describes color in terms of three axes: L* (how light or dark the color is), a* (red versus green) and b* (blue versus yellow). A bright pastel aqua color will be located high up the L* axis and about halfway between the blue and green axes. Specific numerical values can be assigned to L*, a* and b* using a color measurement instrument, as discussed in the sections on viewing and measuring color.