Color Language L*a*b*

Color (colorimetry) is a concept invented by man. In fact, it is nothing less than the reflection of light on a surface, which we perceive through our eyes. The colors green, orange or yellow for example are only terms, but do not describe the spectral components of the reflected light of an object.

Therefore, a kind of color language is needed to describe the spectral components of a certain color, which humans cannot discuss (such as sky blue, deep blue, ocean blue or light blue). A language had to be created that describes all the colors visible to humans, in the words of a computer.

This language is called Lab, where L* stands for lightness (on a scale from 0 (black) to 100 (white), a* for red (+/positive) to green (-/negative), and b* for yellow (+/positive) to blue (-/negative).

L*a*b* is the most widely used and recognized color matching system for describing colors with numbers. For graphics we use RGB (the primary colors of light Red, Green, Blue) as the color model for electronic devices, while CMYK (Cyan, Magenta, Yellow, Key (Black)) are the primary colors of pigment for the printing world. The disadvantage of both models, however, is that neither is able to reproduce all the colors that the human eye can perceive. This can cause problems, as designers and printers have to work within the limits of the available color reproduction devices.

L*a*b* is a device-independent color model used as a reference because it approximates human vision.