Chromaticity determination of pigments and coatings

The chromaticity test of the pigment sample uses a precision Colorimeter to measure the Lab  value. During the test, the sample is made into a circular tablet with a diameter of  4cm  , and then the calibrated Colorimeter is used. In order to reduce the test error, each sample is continuously tested three times. take the average.

In the chromaticity analysis of the pigment, the chromaticity property  is expressed  by the CIE Lab  value, wherein the L  value represents the lightness  , and the value ranges from 0 ( black ) to  100 ( white ) , and the larger the value, the brighter the pigment; a , b  respectively represent the red-green properties and yellow-blue properties of the pigment, and the value range is between -128  and +128  ;   a  is a positive value for red, a negative value for green, b  is a positive value for yellow, and a negative value for blue ; Use the parameter  c  to represent the color saturation of the pigment, and the calculation formula of c  is shown in (2-2) [54]