A Treatise on Painting/Chapter 243
Chap. CCXLIII.—Whether it be possible for all Colours to appear alike by means of the same Shadow.
It is very possible that all the different colours may be changed into that of a general shadow; as is manifest in the darkness of a cloudy night, in which neither the shape nor colour of bodies is distinguished. Total darkness being nothing but a privation of the primitive and reflected lights, by which the form and colour of bodies are seen; it is evident, that the cause being removed the effect ceases, and the objects are entirely lost to the sight.