In designing such subjects it will be good to bear in mind as a guiding principle that no matter what excuse there may be in the nature of the inferred position of the leaf or limb, the outline against the background must be at once agreeable and explanatory.
Every kind of work in relief develops a species of compromise in the expression of form, lying somewhere between the representation of an object on a perfectly flat ground, as in a painting, and the complete realization of the same form, copied from nature in some solid material, without any background whatever. In proportion to the amount of actual projection from the background, of course the necessity diminishes for that kind of foreshortening which is obtained by delineation. It might be inferred, therefore, that in very low relief—which is more nearly akin to the nature of a picture—more liberty may be taken in this direction. It is not so, however, for where actual depth or projection exists, as in carving, be it only so much as the depth of a line, it makes foreshortening well-nigh impossible, except to a very limited extent. There must be, of course, some appearance of this quality, so a certain conventional standard has been set up, beyond which one only ventures at one's own risk. Thus, care is taken that every object composing the subject lies with its longest lines parallel to the background. In this way the least possible violence is done to the imagination in completing the picture. As an example, no single leaf should be represented in relief as turning or coming forward more than it would do if plucked from the tree and laid loosely down upon a sheet of paper. A, Fig. 71, is an outline of an apple-leaf pressed out flat. B is an attempt to present it in violent foreshortening, showing its back to the spectator, while its point is supposed to be buried in the background. C is the same leaf turned the other way, and supposed to be projecting forward; both are exceedingly awkward and unintelligible as mere outlines, and if expressed in relief would not be any more convincing as portraits of the thing intended—rather less so, in fact, than the diagram, which has no projection to interfere with the drawing. So we must turn our leaf until it presents its long side more or less to the spectator, as in D; but even here part of the edge is so thin at a that it will be better to turn it a little farther, as in E, showing more of its surface, as at b.
Fig. 71.
Again, if we take as another example two apples, one partly covering the other, as in a, Fig. 72, where one apple is supposed to be behind the other, and so implies distance. There is no means of expressing this distance in carving. Lowering the surface of the hindmost apple would merely throw out the balance of masses without giving a satisfactory explanation of its position, while to cut a deep groove between the two would be an equally unsightly expedient. The difficulty should, whenever it is possible, be avoided by partially separating the two forms, as in b, where the center of the hindmost apple clears the outline of the other; thus making it possible to get a division without awkwardness.
Fig. 72.