Lightness and Brightness and Other Confusions

From here Itten goes on to give precise instructions on how to carefully mix
the secondaries and the intermediate colour between the secondaries and
primaries, thus arriving at the 12 hues in a beautifully symmetrical and circular
arrangement. As every art student, who has tried to follow Itten’s instructions
knows, it is impossible to create the desired circle from Itten’s starting
points. Itten’s primaries will not yield the 12 hues as instructed and the student
will always have to resort to bending the rules in order to achieve a balanced
result. What Itten has defined here are in fact not the subtractive primaries
of painting, but three of the so-called psychological primaries of vision
and the brain, alluded to above by David Hubel and originally described by
Ewald Hering in 1872.
Figure 18. Johannes Itten’s 12-hue circle from The Art of Colour, 1973 (Original
German edition: Kunst der Farbe, 1961).
Itten’s colour circle (like those of many others) is an idealisation. It stands
aloof from the real world as an abstracted symbol of ideas about colour. The
three primaries, their derivatives and interrelations, as they are presented in
his book, are a mixture of perceptual relations and transcendentalism. It is
strange, though, that despite being an accomplished painter, Itten could not
see the obvious disagreement between the transcendental and the technological
– or perhaps he simply chose to ignore it.
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