COLOR MEASUREMENT OF MICA PIGMENTS

Mica pigments show selective reflection of light. They show a certain color in reflection and the complementary color in transmission. The changes of these colors can be evaluated colorimetrically, if the illumination angle is fixed. As soon as the angle of illumination is changed, the color seen in reflection is shifted considerably. This effect can be demonstrated by measurements where the angle of view is fixed and the angle of illumination ig varied. With the goniometer-measuring head GK 311/M of Carl Zeiss this kind of measurements can be performed, because both angles can be varied by moving illumination and viewing optics independently.