There seems to be a strife between opposing forces at the basis of all things, a strife in which a perfect balance is never attained, or life would cease. The worlds are kept on their courses by such opposing forces, the perfect equilibrium never being found, and so the vitalising movement is kept up. States are held together on the same principle, no State seeming able to preserve a balance for long; new forces arise, the balance is upset, and the State totters until a new equilibrium has been found. It would seem, however, to be the aim of life to strive after balance, any violent deviation from which is accompanied by calamity.

And in art we have the same play of opposing factors, straight lines and curves, light and dark, warm and cold colour oppose each other. Were the balance between them perfect, the result would be dull and dead. But if the balance is very much out, the eye is disturbed and the effect too disquieting. It will naturally be in pictures that aim at repose that this balance will be most perfect. In more exciting subjects less will be necessary, but some amount should exist in every picture, no matter how turbulent its motive; as in good tragedy the horror of the situation is never allowed to overbalance the beauty of the treatment.
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Between Straight Lines and Curves

Let us consider in the first place the balance between straight lines and curves. The richer and fuller the curves, the more severe should be the straight lines that balance them, if perfect repose is desired. But if the subject demands excess of movement and life, of course there will be less necessity for the balancing influence of straight lines. And on the other hand, if the subject demands an excess of repose and contemplation, the bias will be on the side of straight lines. But a picture composed entirely of rich, rolling curves is too disquieting a thing to contemplate, and would become very irritating. Of the two extremes, one composed entirely of straight lines would be preferable to one with no squareness to relieve the richness of the curves. For straight lines are significant of the deeper and more permanent things of life, of the powers that govern and restrain, and of infinity; while the rich curves (that is, curves the farthest removed from the straight line) seem to be expressive of uncontrolled energy and the more exuberant joys of life. Vice may be excess in any direction, but asceticism has generally been accepted as a nobler vice than voluptuousness. The rococo art of the eighteenth century is an instance of the excessive use of curved forms, and, like all excesses in the joys of life, it is vicious and is the favourite style of decoration in vulgar places of entertainment. The excessive use of straight lines and square forms may be seen in some ancient Egyptian architecture, but this severity was originally, no doubt, softened by the use of colour, and in any case it is nobler and finer than the vicious cleverness of rococo art.

221We have seen how the Greeks balanced the straight lines of their architectural forms with the rich lines of the sculpture which they used so lavishly on their temples. But the balance was always kept on the side of the square forms and never on the side of undue roundness. And it is on this side that the balance would seem to be in the finest art. Even the finest curves are those that approach the straight line rather than the circle, that err on the side of flatnesses rather than roundnesses.
Between Flat and Gradated Tones

What has been said about the balance of straight lines and curves applies equally well to tones, if for straight lines you substitute flat tones, and for curved lines gradated tones. The deeper, more permanent things find expression in the wider, flatter tones, while an excess of gradations makes for prettiness, if not for the gross roundnesses of vicious modelling.

Often when a picture is hopelessly out of gear and "mucked up," as they say in the studio, it can be got on the right road again by reducing it to a basis of flat tones, going over it and painting out the gradations, getting it back to a simpler equation from which the right road to completion can be more readily seen. Overmuch concern with the gradations of the smaller modelling is a very common reason of pictures and drawings getting out of gear. The less expenditure of tone values you can express your modelling with, the better, as a general rule. The balance in the finest work is usually on the side of flat tones rather than on the side of gradated tones. Work that errs on the side of gradations, like that of Greuze, however popular its appeal, is much poorer stuff 222than work that errs on the side of flatness in tone, like Giotto and the Italian primitives, or Puvis de Chavannes among the moderns.
Between Light and Dark Tones.

There is a balance of tone set up also between light and dark, between black and white in the scale of tone. Pictures that do not go far in the direction of light, starting from a middle tone, should not go far in the direction of dark either. In this respect note the pictures of Whistler, a great master in matters of tone; his lights seldom approach anywhere near white, and, on the other hand, his darks never approach black in tone. When the highest lights are low in tone, the darkest darks should be high in tone. Painters like Rembrandt, whose pictures when fresh must have approached very near white in the high lights, also approach black in the darks, and nearer our own time, Frank Holl forced the whites of his pictures very high and correspondingly the darks were very heavy. And when this balance is kept there is a rightness about it that is instinctively fel............