Rooms painted black appear much smaller than white ones. Black furniture dominates the space. In the most positive case they appear representative, in the most negative case they are oppressive. A black sofa appears to be harder than a white one. Colours influence the impression one gets of size, weight and material. Boxes with a light colour will be assessed less heavily than dark ones. The impression of the weight is not only due to the colour. The material usually gives the deciding factor. Every effect is the sum of all experiences.
(Heller, 1989)