"When you are representing a white body surrounded by ample space, since the white has no colour in itself it is tinged and in part transformed by the colour of what is set over against it. If you are looking at a woman dressed in white in the midst of a landscape the side... exposed to the atmosphere... since this atmosphere is itself blue, the side of the woman which is exposed to it will appear steeped in blue. ...[A]ll the parts of the folds [of her dress] which are turned towards the meadow will be dyed by the reflected rays to the colour of the meadow; and thus she becomes changed into the colours of the objects near, both those luminous and those nonluminous."