Brightness, Opacity & Color Tester - ISO type The Brightness & Color Meter makes measurement of brightness, color and opacity affordable in Production and QC applications. The Brightness & Color Meter measures color, color purity, degree of yellowness, degree of whiteness, color matching and color fastness. Fluorescence measurement. Measures the effect of fluorescent additives by use of a removable ultra-violet filter. TAPPI T567pm-97 ISO/TC6/WG3/ N1116.