When working, the colorimeter generally relies on the CIELab color space, and outputs L, a, b values, and color difference values such as △L, △a, △b, △E after colorimetry by comparing the color difference values between the sample and the standard. This article introduces the range of L, a, b of the colorimeter and the meaning of Lab color difference values.

The color difference unit, NBS, is derived from the unit of color difference formula which is established by Judd-Hunter. In 1939, the American Bureau of Standards adopts this color difference formula and calculates the color difference acc

There are three major elements to perceive color: light, object and observer. Any change of these three elements will influence the observers color perception. When the light source and the observer dont change, then the object will determi

In the visual observing situation, the observer is the human eye that receives the light reflected from or transmitted through an object, and the brain which perceives the vision. The visual observing situation Since different humans percei