CLXXVII
Chiaroscuro, to use untechnical language and to speak of it as it is employed by all the schools, is the art of making atmosphere visible and painting objects in an envelope of air. Its aim is to create all the picturesque accidents of the shadows, of the half-tones and the light, of relief and distance, and to give in consequence more variety, more unity of effect, of caprice, and of relative truth, to forms as to colours. The opposite conception is one more ingenuous and abstract, a method by which one shows objects as they are, seen close, the atmosphere being suppressed, and in consequence without any perspective except the linear perspective, which results from the diminution in the size of objects and their relation to the horizon. When we talk of aeriel perspective we presuppose a certain amount of chiaroscuro.
Fromentin.