Concentration: blue 19%, white 19%, black 13%, …
Heller (1989)

Depth: blue 54%, grey 13%, white 10%, …
Heller E. (1989)

Sensible: white 26%, blue 22%, silver 11%, gold 11%, …
Heller (1989)

Research into the orientation of Impressionist or Expressionist paintings shows that expressionism, with mainly portraits and still lives as the subject, has a majority of vertical paintings. While impressionism, with landscapes or outer views as an important subject, counts the most horizontal paintings. Verticality has deeper subjects than horizontal. “They sought around with the eye and not in the mysterious depths of the mind.” Gauguin, about the superficial representation of reality among the Impressionists.
(Alpaerts, 1980)

Blue is one of the main colours of the virtues of labor and mind. The first colour of intelligence and science is now called the neutral, impartial white. But in old symbolism, blue is the colour of the intellectual faculties.
Heller E. (1989)