... tester is the professional instrument to test the object of the whiteness ,yellowness,chromatic aberration,opacity, transparency, light ... )4.Measure .ceramic’s whiteness5.Measure the wihteness of building materials and non-metallic mineral products6.Measure Yellowness ... off protection, Correct data would not lose8.can store 9 reference samples ( sample or data)Technical parameters1.Power :220V±10%, ...