The color of the samples exposed to a degradation test is measured before and after the test using a colorimeter or spectrocolorimeter. The details vary from one test method to another.
Laboratory measuring instruments are often used in the industry to check the color of manufactured products compared to a color standard. Obtaining the following coordinates:
ΔL * = difference in lightness and darkness (+ = lighter, - = darker)
Δa * = difference in red and green (+ = redder, - = greener)
Δb * = difference in yellow and blue (+ = yellower, - = bluer)
ΔE * = total color difference (total color difference of the three coordinates)
Equipment: Portable Spectrophotometer, Model: MiniScan XE Plus, Hunter Lab.
Standards: ISO 105 -A02, FLTM BI 109-01, SAE J1545, VW 50190, among others.