When such departures from the truth of things are properly motivated, no one can be offended by them, any more than when the brilliant hues of nature appear black and white in a charcoal drawing. The amount of realism in any work of art is largely a matter of tacit convention. An artist may, if he wishes, use color with no pretense at giving back the real colors of objects, but for purely expressive purposes alone, relying on line for purposes of representation. This is often done in Japanese prints. All that is necessary is that we should understand what the artist is doing and find what he presents to us real and alive. On the other hand, an expressive use of color and line leading to a distortion of objects out of all possibility of recognition, or even a use which makes them seem unreal and awry, is without excuse. For since colors and lines are employed to bring things before the imagination, they should be made to serve this purpose successfully; the value which belongs to the things should have a chance to appear; but this can happen only if they seem to be actually present before us. Painting is not a mere music of color and line expressive of abstract and objectless emotions alone, but a poetry, which, through the picturing of objects to which emotions are attached, renders the latter concrete and definite. Not mere feeling, such as a color or a line by itself can convey, but feeling in the presence of nature, which can be expressed only when color and line are made into a recognizable image of nature, is the substance of painting. One cannot express the feeling of the weight and bulk of objects, of their distribution in three dimensions, or the value of their shadows or atmospheric enveloping, without the representation of weight and bulk and shadow and atmosphere and perspective. Every increase in the power to represent nature, every advance in the mastery of the object, adds a new power over the expression of feeling, which varies with the object. The realist is, therefore, right in his demand that nature itself be painted; only he should remember that the nature which presents itself in art is never the naked object, but veiled in feeling; and, as so veiled, may sometimes be seen pretty much as it really is; then again with parts concealed, and sometimes even transformed. Both a realism that tries to unite fidelity to the full qualities of the object with musical expression in the medium, and so to render the more typical responses to nature, which depend, for the most part, on the object itself, and a symbolism or expressionism that sacrifices fidelity for the expression, through the mere medium, of more personal responses, are in their rights. Only the limits of both tendencies are illegitimate--the use of color and line to produce mere images of things on the one hand, or purely musical effects on the other.