What is the difference between the 420:520 ratio measurement of hue and CIE hue angle?
The 420:520 hue ratio is based on two wavelengths: the 420 nm for indicating yellow and the 520 nm for red. In contrast, the CIE hue angle is based on the entire wine spectra. Hue angle is more descriptive of color nuance and, as a result, is more sensitive to subtle changes in wine chemistry and a more accurate representation of color present. What’s more, the CIE hue angle can describe any color. The 420:520 ratio is only appropriate for red wines.
