Chromaticity measurements of retroreflective material under nighttime geometry

Chromaticity measurements of three different types of retroreflective material in six common colors are presented. A computer controlled spectroradiometric retroreflectometer system with sample goniometer was employed for the measurements. Geometry-caused chromaticity changes were as great as 0.05 in x and y. Color differences in both CIELUV and CIELAB computed from a base geometry of alpha = 0.2 and beta = -4 degrees attained values as high as 50 units for some materials. The total color extent of each material is plotted from a 4 x 4 measurement matrix of angles. plotted on the CIE 1931 diagram.