Chap. CCXXXVIII.—That the Beauty of a Colour is to be found in the Lights.
As the quality of colours is discovered to the eye by the light, it is natural to conclude, that where there is most light, there also the true quality of the colour is to be seen; and where there is most shadow the colour will participate of, and be tinged with the colour of that shadow. Remember then to shew the true quality of the colour in the light parts only [56].
Chap. CCXXXIX.—Of Colours.
The colour which is between the light and the shadow will not be so beautiful as that which is in the full light. Therefore the chief beauty of colours will be found in the principal lights[57].
Chap. CCXL.—No Object appears in its true Colour, unless the Light which strikes upon it be of the same Colour.
This is very observable in draperies, where the light folds casting a reflexion, and throwing a light on other folds opposite to them, make them appear in their natural colour. The same effect is produced by gold leaves casting their light reciprocally on each other. The effect is quite contrary if the light be received from an object of a different colour [58].
Chap. CCXLI.—Of the Colour of Shadows.
The colour of the shadows of an object can never be pure if the body which is opposed to these shadows be not of the same colour as that on which they are produced. For instance, if in a room, the walls of which are green, I place a figure clothed in blue, and receiving the light from another blue object, the light part of that figure will be of a beautiful blue, but the shadows of it will become dingy, and not like a true shade of that beautiful blue, because it will be corrupted by the reflexions from the green wall; and it would be still worse if the walls were of a darkish brown.