Mouldings are perhaps the most important of all the devices employed by the architect for ornamental purposes. In their simplest form they produce bands of shadow varying in intensity according to the contour of the moulding. These shadow combinations may be controlled at will by the designer and are greatly enriched, when desired, by ornamenting the moulding itself.
On Plate 75 are given the typical mouldings and the shadow effect produced by each when in the direct sunlight. When these mouldings are entirely in the shadow of some other object, their own shadow effect differs from that shown. This is because of the fact that a member in such a shadow receives reflected light from bright surfaces below. Reflected lights may be considered as coming in exactly the opposite direction from the conventional light ray as described on page 33. The effect of reflected light may be seen in the shaded portions of the given mouldings.
The accompanying plate illustrates the type of ornament typical to each of the various moulding contours. It will be noticed that in each case the ornament echos in a way the profile of the moulding. Thus the ornamental egg is similar in shape to the Ovolo, the graceful waving leaf to the Cyma, the bundle of reeds to the Torus, etc.
A study of Plates 62 to 72 will show how uninteresting the Orders would become if the mouldings were omitted; it will also give the student some idea as to the importance of mouldings in architectural design.
The scale of a moulding, or the degree of fineness with which its parts are designed, is largely dependent upon the material in which it is to be executed. Thus mouldings in stone must of necessity be bolder than those in wood. Finer mouldings may be run in hard, close-grained woods than in those of coarser texture, and mouldings in metal may be designed on as small a scale as desired. The method of producing the moulding must also be considered by the designer, as this has a definite bearing on the design. A wooden moulding, if undercut, can not be made in one piece by machinery. When such a moulding is to be used, it must be made in parts, which is not desirable, or else by hand. In the latter case the cost usually makes its use impracticable. Study carefully the effects of light and shade on the many surfaces of the ornamented mouldings.