... Measure ISO(R457)and Rz,Rx,Rz and yellowness index IntroductionZB-A colour tester is the professional ... the color of object , report diffuse reflectance factor Rx, Ry, Rz;stimulus value X10, Y10, Z10; ... chromaticity coordinate x10, y10, z10;lightness L*;chrominance a*, b*;chromaticity C*ab;hue angle h*ab; ... ’s stability: ≤0.1 within 30min4.Repeatability:Rx Ry and Rz s≤0.01 ,chromaticity coordinate ...