| 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 (related to color saturation)
is maximal and the color of four times more diluted (or
thinner) and four times more concentrated (or thicker)
sample. The two hue angle differences are called
dichromaticity index towards lighter (DIL) and
dichromaticity index towards darker (DID)
respectively. The dichromaticity index 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 (for 44 degrees in Lab color space) when the
thickness of the observed layer is increased from cca 0.5 mm
to 2 mm; and it changes slightly towards green (for 9
degrees) if its thickness is reduced for 4-fold.
Follow the link to download free Dichromaticity Index Calculator software, and a test
pumpkin seed oil spectrum,
or any other spectrum in .txt file format.
(Please note that after installation the application may
take several seconds to start. Some computers may need to be
restarted after the installation.)
Alternatively, you can also download the
algorithm in
Excel file. You will need to enable macros in MS
Excel.
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