ZB-A colour tester Measure ISO(R457)and Rz,Rx,Rz and yellowness index IntroductionZB-A colour tester is the professional instrument to test the ... the color of object , report diffuse reflectance factor Rx, Ry, Rz;stimulus value X10, Y10, Z10;chromaticity coordinate x10, y10, z10 ... ’s stability: ≤0.1 within 30min4.Repeatability:Rx Ry and Rz s≤0.01 ,chromaticity coordinate s≤0.0010,.R457 s ...