Color contrast in a liquid crystal display using dye dichroism is investigated experimentally. Nematic liquid crystal with a positive dielectric anisotropy is used as the host. Three kinds of merocyanine dye are used as the guest. Optimum solubility of the dye is decided, and its criteria, taking account of the color difference, is established. The color difference is given in the 1976 CIE (L*, a*, b*) color scale. The contrast ratio values show good correlation with observed estimated values, and the validity of the criteria is confirmed.