Das Rätsel der farbigen Schatten
When an object is illuminated by two different light sources, two coloured halfshadows appear on a projection screen. If one light is white, it illuminates the shadows of the other light with the latter’s complementary colour. Steiner, Proskauer and Ott, all closely familiar with Goethe’s colour theory, contradict Goethe on the issue of whether the complementary shadow colour is subjectively physiological or objectively physical. This contradiction is analysed and discussed in the light of the arguments and reasons. The basics of Küppers’ modern colour theory are presented and related to Goethe’s comments. On this basis, and with introduction of my own experiences from experiments, Goethe’s classification of the phenomenon of complementary colours of shadows as physiological colours is confirmed.