Purpose of Contour Enrichment
It is the purpose of enrichment to add to the problem (1) grace; (2) lightness; (3) variety; (4) unity. If it is applied in a proper manner it should likewise add to the apparent structural strength. We should carefully guard the design, therefore, against (1) enrichment that has a tendency to obscure or destroy the structural lines; in other words, enrichment that is not subordinated to the structure, and (2) enrichment that adds nothing to the structure by its application; that is, one which does not increase either the apparent strength or the beauty of the object.
Requirements of Contour Enrichment
As an example of this first point, the turned candlestick with the candle supported by a stack of turned balls alternating with tauri or thin discs tends to obscure completely the sense of support. Again, the landscape gardener feels that he is violating a fundamental principle in design if by planting vines to grow around a building, he obscures the foundation, and the roof appears, consequently, to rest on and be supported by the stems and leaves of the vines. Thus it is seen that the eye registers a sense of structural weakness when the main supports of an object disappear and are no longer to be traced under the enrichment.
Under the second point falls the indiscriminate placing of unrelated objects in the contour enrichment. Naturalistic objects similar to the claw foot and the human head, for example, should give way to natural curves that add to the appearance of total strength. Where are we to find these curves suited to our purpose?
Valuable Curves for Outline Enrichment
Up to this point emphasis has been placed upon straight and curved lines immediately connected with pure service. For grace and lightness it is necessary to depart at times from the rigidity of straight lines. To understand the character of this departure let us consider a simple bracket as a support for a shelf.
This bracket acts as a link, connecting a vertical wall or leg with a horizontal member or shelf. A bracket shaped like a 45-degree triangle, [Figure 10], [page 24], gives one the sense of clumsiness. If the feeling of grace is to be imparted the eye must move smoothly along the outline of the bracket, giving one a sensation of aesthetic pleasure. A curved line will produce this effect more completely than will a straight line. One must likewise get the feeling that the curve of the bracket is designed to support the shelf.