The message of impressionism is _light,_ as the effort of the early painters was _to secure light,_ the quest of all the philosophies. The impressionist calls upon every part of his work to speak of light, the middle tint, the high lights and the shadow all vibrating with it. From the decorative point of view alone, the picture, as a surface containing the greatest amount of beauty of which the subject is capable is more beautiful when varied by many tones, or by few, _in strong contrast,_ than when this variety or contrast is wanting. Those decorative designs have the strongest appeal in which the balancing measures are all well defined. There are schemes of much dark and little light, or the reverse, or an even division, and in each case the balance of light and dark is sustained; for when there is little dark its accenting power is enhanced and when little light is allowed, it, in the same manner, gains in attraction. But light and dark every work of art must have; for to think of light without dark is impossible. When, therefore, the artist begins a picture his first thought is what is to be the scheme of light and shade? The direction or source of the light helps a decision. The illumination of the subject is a study most easily proceeded with by induction, from particular cases to general conclusions.
[A Reversible Effect of Light and Shade (The Same Subject Vertically and Horizontally Presented)]
The effectiveness of the first of the two reversible _photographs_ is as great as the last and the subject as picturesque though it be discovered that the first is the second placed on end. It is able to satisfy us not only because of the happy coincidence that the leaves upon the bridge represent bark texture and the subdued light upon its near end creates the rotundity of the trunk or that a distant tree serves as the horizontal margin of a pool, but because its light and shade is conceived upon the terms of balance expressing in either position one of the fundamental forms of light and shade and lineal construction, that of the rectangle in either light or dark together with an oppositional measure—the light through the distant trees.
With the history of art and the world’s gallery of painting spread out before us, we may take a continuous view of the whole field. Leaving out the painters of the experimental era let us begin with the great masters of effect.