The starting point is the study of colour and its effects on men.

There is no need to engage in the finer shades of complicated
colour, but rather at first to consider only the direct use of
simple colours.

To begin with, let us test the working on ourselves of individual
colours, and so make a simple chart, which will facilitate the
consideration of the whole question.

Two great divisions of colour occur to the mind at the outset:
into warm and cold, and into light and dark. To each colour there
are therefore four shades of appeal--warm and light or warm and
dark, or cold and light or cold and dark.

Generally speaking, warmth or cold in a colour means an approach
respectively to yellow or to blue. This distinction is, so to
speak, on one basis, the colour having a constant fundamental
appeal, but assuming either a more material or more non-material
quality. The movement is an horizontal one, the warm colours
approaching the spectator, the cold ones retreating from him.

The colours, which cause in another colour this horizontal
movement, while they are themselves affected by it, have another
movement of their own, which acts with a violent separative
force. This is, therefore, the first antithesis in the inner
appeal, and the inclination of the colour to yellow or to blue,
is of tremendous importance.

The second antithesis is between white and black; i.e., the