How necessary in Art

From the necessity of gradation results what is commonly given as a rule of art, though its authority as a rule obtains only from its being afact of nature, that the extremes of high light and pure color, can exist only in points. The common rules respecting sixths and eighths, held concerning light and shade, are entirely absurd and conventional; according to the subject and the effect of light, the greater part of the picture will be or ought to be light or dark; but that principle which is not conventional, is that of all light, however high, there is some part that is higher than the rest, and that of all color, however pure, there is some part that is purer than the rest, and that generally of all shade, however deep, there is some part deeper than the rest, though this last fact is frequently sacrificed in art, owing to the narrowness of its means. But on the right gradation or focussing of light and color depends in great measure, the value of both. Of this, I have spoken sufficiently in pointing out the singular constancy of it in the works of Turner. Part II. Sect. II. Chap. II. § 17. And it is generally to be observed that even raw and valueless color, if rightly and subtilely gradated will in some measure stand for light, and that the most transparent and perfect hue will be in some measure unsatisfactory, if entirely unvaried. I believe the early skies of Raffaelle owe their luminousness more to their untraceable and subtile gradation than to inherent quality of hue. oil paintings online