A Treatise on Painting/Chapter 244
Chap. CCXLIV.—Why White is not reckoned among the Colours.
White is not a colour, but has the power of receiving all the other colours. When it is placed in a high situation in the country, all its shades are azure; according to the fourth proposition[1], which says, that the surface of any opake body participates of the colour of any other body sending the light to it. Therefore white being deprived of the light of the sun by the interposition of any other body, will remain white; if exposed to the sun on one side, and to the open air on the other, it will participate both of the colour of the sun and of the air. That side which is not opposed to the sun, will be shaded of the colour of the air. And if this white were not surrounded by green fields all the way to the horizon, nor could receive any light from that horizon, without doubt it would appear of one simple and uniform colour, viz. that of the air.
- ↑ See chapters ccxlvii. cclxxiv. in the present work. Probably they were intended to form a part of a distinct treatise, and to have been ranged as propositions in that, but at present they are not so placed.