Kreft's dichromaticity index (DI) is a measure for quantification of dichromatism. It is defined as the difference in hue angle (Δhab) between the color of the sample at the dilution, where the chroma is maximal, and the color of four times more diluted and four times more concentrated sample. The two hue angle differences are called the dichromaticity index towards lighter and dichromaticity index towards darker respectively. Kreft's dichromaticity indexes DIL and DID for pumpkin seed oil, which is one of the most dichromatic substances, are −9 and −44, respectively. This means, that pumpkin seed oil changes its color from green-yellow to orange-red when the thickness of the observed layer is increased from cca 0.5 mm to 2 mm; and it changes slightly towards green if its thickness is reduced for four-fold.