Colorimetric analysis of the color of light passed through a birefringent crystal placed between Nicol prisms is treated more generally than hitherto discussed, by adding an achromatic retardation. It is found that, by proper choice of the achromatic retardation, the color change with respect to the change of birefringence becomes very sensitive and we call this “hypersensitive (polarization) color.”
The case when the crystal has the power of rotating the plane of polarization, which can be treated in the same way, is also shown.
Then the color of thin layers of dielectrics on a metallic surface is analyzed. This can be treated as an extension of the cases of polarization color. As it is difficult to give a general solution, some special cases (so called cases of “white metal”) are given and the color of the reflected light is calculated and plotted on CIE chromaticity diagram.
HIROSHI KUBOTA and TERUJI OSE, "Further Study of Polarization and Interference Colors," J. Opt. Soc. Am. 45, 89-96 (1955)