Every colour shade that is obtained from a particular plant has a quite distinctive character. The red of the madder root is quite different from brazil wood red, just as buckthorn berry yellow is different from mignonette yellow. Another characteristic feature of plant colours is that each colour shade embodies further nuances from the range of the complementary colours. It is well known, for instance, that chlorophyll (leaf green) contains purple. The different colour shades in leaf green thus add up to a totality which is at the same time alive and in motion. This absence of any kind of one-sidedness explains the soothing harmony of plant colours, both in their effect on the soul and the feelings and in the mutual interplay of the individual colours.

Synthetic colours on the other hand, being derived from just one basic substance (mineral oil or tar), are quite undifferentiated in their effects. They lack that living vitality that we find in plant colours. Even under electric light, and especially when the lighting is diffuse, plant colours appear exceptionally alive.