Contrast in form or colour imparts vigour to the composition; the commonest illustration of contrast in form is the circle and the straight line, but more subtle contrasts are found in Nature’s works, very flat curves being contrasted with sharp ones; and in colour, besides the contrasts of the leaves and flowers, there are often spots of contrasting colour on flowers to heighten their brilliancy, though this is mostly effected by the pistils and stamens. The “egg and tongue,” one of the most effective ornaments invented, has the smooth curved eggs contrasted with the thin lines of the shells, and the curved eggs with the straight edge of the tongue. ([Fig. 67].) Renaissance and Roman ornament (see [Fig. 129]) give the amplest illustrations of contrast; varieties of foliage contrasting with vases, labels, shields, armour, masks, animals, and human figures. (See Figs. [121], [123], [124], [126], [127], [130], [132], and [Frontispiece.])
Symmetry has been defined before as the mere doubling of a form on its axis; it is one of the most important means of producing ornament, as well as one of the laws most commonly found in nature. Nothing in nature, however, is absolutely symmetrical, though there is a suggestion of symmetry about the bulk of its works.
Radiation is the spreading out of lines from a point, like a fan, and these lines may be straight or curved, and the axis of the radiating lines may be vertical, horizontal, or oblique. It is found in the human hand, in the wing feathers of birds, in the scallop and similar bivalve shells, in the umbels of flowers, and in much other plant growth. The Greek honeysuckle is the most beautiful instance of its adaptation as ornament. (See Figs. [49], [50], [51], [52] and [115].) If the centre of the radiating lines is kept below the springing line, it adds greatly to the interest and beauty of the ornament. A succession of festoons or of drapery hanging from two points are examples of one species of curved radiation.
Tangential Junction.—Euclid’s definition of a tangent is as follows:—“A straight line is said to touch a circle, when it meets the circle, and being produced does not cut it,” and is obtained by drawing a line perpendicular to any radius from the point at which it touches the circumference. In ornament, tangential junction means that where two curves of opposite curvature meet they are to meet at the tangential points of each ([Fig. 25]), and in the case of a curve being continued by a straight line, the point of junction is the tangential point. A curve, however, should never be continued by a straight line, but by a flatter curve. The beauty imparted by following this rule is seen in the Ionic capitals of the Temple of Apollo at Bassæ, where the two volutes are joined by a curve instead of by the usual straight line (see [Fig. 179] in Appendix).
Repose.—The absence of a look of motion in ornament; this appearance of motion may be seen in some flamboyant tracery and Saracenic patterns, in some modern paper-hangings, and in patterns in woven and printed stuffs. The word repose is sometimes used to denote an absence of spottiness. In the best pilaster panels, horizontal lines are introduced partly for contrast, and partly to give repose by checking the appearance of motion in the curved plant forms. ([Fig. 127].)
Variety is a difference of form or arrangement in the ornament from that which immediately precedes or follows it. In nature we see that every leaf varies from every other by subtle differences, though the foliage is roughly alike, and it is for this reason that Nature’s works never pall upon us. General similarity with slight variety is the most proper for the highest and most dignified ornament. In other cases absolute variety is permissible. Variety is the salt of ornament that takes off the insipidity of repetition.
Subordination.—The state of being inferior to another, a regular descending series. In any complex system of ornament, one part should be chosen as the most important, and all the rest should lead up to it; but certain distinct parts, such as masses or flowers, may re-echo in a fainter way the main motive. In drawing, subordination is obtained by the principal mass being larger than the rest, and by its details being larger and more pronounced; in painting, by the above and by the principal part being more vivid in colour; in modelling, by greater size and relief. The Romans and Cinque Cento artists were great masters of this art. In some panels, though the highest relief is not great, there is an infinity of gradation, the lowest relief gradually sinking into the ground. In a Renaissance bas-relief of a full face the greatest projection is about the sixteenth of an inch, and yet the face is perfectly modelled. Modern English carved ornament is too frequently deficient in this quality.
Balance.—The making unsymmetrical masses of equal weight. In the creations of nature we see balance employed in trees, shrubs, and plants ([Fig. 160]); in leaves, made as it were on a symmetrical basis, balance is equally employed. In simple oval leaves, for example, one side is more convex than the other, and the balance is got by the curve in the rib.
Unity is the completeness of any system of ornament not marred by incongruous elements or forms.
Series is the repetition of a limited succession of different forms: in the egg and tongue, of two; in the bead and reel, of three; in branches of plants when the leaves regularly diminish in size, of many. Fig. [67].) Long series may be seen in Saracenic ornament, where the same text is repeated sometimes with ornament between the texts.