Color Knowledge Introduced: the CIELAB Color Space

In the past, many of the color difference formula to the practical industrial application called a big inconvenience becauseof the different between the color formula for mutual conversion of data difficult or impossible, the result of the

different between the calculated ratio of the non-interoperability.

To change this chaotic situation, uniform color evaluation criteria, the International Commission on Illumination (CIE) in

1976 recommended a very uniform color space CIELAB color difference formula corresponding to unify the application of

color difference formula, making the application more colorimeter general , widespread.

CIELAB uniform color space is a three-dimensional system, the color of the three-dimensional distribution as shown in

Figure 1. Since its inception in CIELAB color space, based on this principle colorimeter developed in the industrial sector has

been widely used, especially in the manufacture of printing and dyeing pigments, paints, textile printing and dyeing, printing

ink, plastic industry products such as coloring color quality control has a very important position.

Chroma composition of a and b represents the color of the chroma plane, Figure 2 is a graph saturation, wherein, + a

represents red,-a represents green, + b represents yellow,-b represents blue, and green, which has a non-red , the relationship

between non-yellow is blue.

Figure 3 is a lightness value L, which means that the degree of light and dark color, which ranges from 0 to 100.