Pen Drawing. (An Illustrated Treatise)

Art, with its finite means, cannot hope to record the infinite variety and complexity of Nature, and so contents itself with a partial statement, addressing this to the imagination for the full and perfect meaning. This inadequation, and the artificial adjustments which it involves, are tolerated by right of what is known as artistic convention; and as each art has its own particular limitations, so each has its own particular conventions.
Sculpture reproduces the forms of Nature, but discards the color without any shock to our ideas of verity; Painting gives us the color, but not the third dimension, and we are satisfied; and Architecture ispurely conventional, since it does not even aim at the imitation of natural form. It is a recognized principle that every medium of art expression should be treated with due regard to its nature and properties.
The sculptor varies his technique according as he works in wood, granite, or marble; the painter handles his water-color in quite another manner than that he would employ on an oil-painting of the same subject; and the architect, with the subtle sense of the craftsman, carries this principle to such a fine issue as to impart.