White light interferometry yields good resolution in thin film thickness measurements. Hue value variations vs. film thickness variations are complex and furthermore dependent on the power spectrum of the light source.Absolute film thickness measurements is possible using white light interferometry.
Olov Marklund, Lennart Gustafsson, "Image Analysis Applied to Film Thickness Measurements with White Light Interferometry" in Proc. IS&T 2nd Color and Imaging Conf., 1994, pp 186 - 189, https://doi.org/10.2352/CIC.1994.2.1.art00051