The received notion, as stated by Du Fresnoy,74 is much too positive and unconditional, and is only true when we understand the "displaying" light to comprehend certain degrees of half or reflected light, and the "destroying" shade to mean the intensest degree of obscurity.
There are degrees of brightness which destroy colour as well as degrees of darkness.75 In general, colour resides in a mitigated light, but a very little observation shows us that different colours require different degrees of light to display them. Leonardo da Vinci frequently inculcates the general principle above alluded to, but he as frequently qualifies it; for he not only remarks that the highest light may be comparative privation of colour, but observes, with great truth, that some hues are best displayed in their fully illumined parts, some in their reflections, and some in their half-lights; and again, that every colour is most beautiful when lit by reflections from its own surface, or from a hue similar to its own.76
The Venetians went further than Leonardo in this view and practice; and he seems to allude to them when he criticises certain painters, who, in aiming at clearness and fulness of colour, neglected what, in his eyes, was of superior importance, namely, gradation and force of chiaro-scuro.77
That increase of colour supposes increase of darkness, as so often stated by Goethe, may be granted without difficulty. To what extent, on the other hand, increase of darkness, or rather diminution of light, is accompanied by increase of colour, is a question which has been variously answered by various schools. Examples of the total negation of the principle are not wanting, nor are they confined to the infancy of the art. Instances, again, of the opposite tendency are frequent in Venetian and early Flemish pictures resembling the augmenting richness of gems or of stained glass:78 indeed, it is not impossible that the increase of colour in shade, which is so remarkable in the pictures alluded to, may have been originally suggested by the rich and fascinating effect of stained glass; and the Venetians, in this as in many other respects, may have