Monotone is tiresome, and to normal persons unendurable. The eye is never satisfied unless the visual field presents a diversity of tones. However, it must first of all be an orderly diversity, as otherwise the effect would be so incoherent that the mind could recognize essential tonal likenesses only with a sense of effort. Disorder is never an esthetic quality, but is rather the most fecund source of ugliness. If, in order to demonstrate this fact experimentally, one will take five small oblongs of plain neutral gray, say one by two inches in size, and varying progressively in tone from dark to light, and will place these oblongs side by side in every possible combination, it will be found that the only esthetically pleasing arrangement is one in which the tones vary progressively from one extreme to the other. Thus the eye is able to take in the whole series with the least effort, and the mind judges of the nature of each tone, perceives without effort the elements of likeness, and is content.

Orderly tone relationships give atmosphere and coherence and organic unity to a decorative treatment, and are as much as any other single factor responsible for its beauty and charm. In the treatment of background surfaces this orderly arrangement will work upward in an ascending scale, from the floor through the walls to the ceiling. Rooms in which this order is reversed by using darker tones on the walls and ceiling and lighter tones on the floor have in general a top-heavy and disturbing appearance, because the mind through age-long processes of association has come instinctively to regard dark-colored forms and surfaces as heavier in weight than light-colored forms and surfaces. Accordingly it wants to see the darker masses below the horizontal center of the room for the sake of stability, with the darkest at the base; and the lighter masses above the horizontal center for the sake of buoyancy and lightness, with the lightest at the top. Thus in a carefully furnished room the three background surfaces, floor, walls and ceiling, constitute three distinct zones,'each characterized by a dominant tone quality. Within each of these zones there may be in good work wide contrast both in hue and in purity. There ought not, however, to be any very wide contrasts in tone, and in general we may say that the less the tranquillity of the zone atmosphere is broken by contrasts of tone, beyond the minimum essential to the proper outline and emphasis of form, the greater will be the chance of beauty in the room.

In practice the tranquillity of the floor zone will be disturbed by the use of a carpet or rug having a dark ground with light ornamental motives or a light ground with dark motives; by a dark rug on a light floor or a light rug on a dark floor, with the effect strikingly intensified, of course, when several small rugs are used; and by the use of light furniture and upholstery fabrics on a dark floor covering or the converse. Similarly the tranquillity of the wall zone will be disturbed by the use of very light walls with dark surbase or dado, trim, or fireplace, or the converse; or by dark hangings, pictures, cabinets or heavy chairs, or even small decorative accessories against markedly light walls, or the converse; while dark beams against a very light ceiling will have the same unesthetic result. This does not mean that tone contrasts within a given zone must be reduced to the extreme minimum; but it does mean that such contrasts must be reduced, both in number and in intensity, to the point where effects of spottiness are eliminated, and the essential tone unity of the zone is instantly apparent.

It is to be noted that contrast can give interest, zest and animation through the opposition of unlike elements either irregularly and as it were capriciously, in which case it serves merely to accent or give snap, or regularly and rhythmically, in which case the contrast itself becomes an element of unity in the composition of the room. A simple illustration is afforded by the case of blue and gold draperies. These colors contrast sharply, both in hue and tone, and when used together they are certain to give an effect of snap and animation, the intensity of the effect depending on the purity of the hues and the area of the contrasting surfaces. In a blue and gold damask or velvet these colors are combined in a repeating design, and the regular and rhythmic recurrence of the same combinations of the two hues constitutes not only a contrast, but a powerful unifying factor in the room. If on the other hand plain blue hangings are trimmed with a gold galloon, or if plain gold hangings are outlined with a gimp or fringe of blue, the contrast serves merely as an accent. Of course this plain blue fringe would in practice be made to repeat a blue in the rug, or in some other important element on or near the floor, thus serving to unify the general scheme; but so far as the hangings alone are concerned its whole function is to set off and emphasize by contrast the peculiar quality of the plain gold.

a.

b.

Figure 21. - (a) Sharp contrast, serving merely to accent and define; (b) same contrast rhythmically repeated, and therefore unifying.

In the design of rugs and furniture, as in the composition of the room as a whole, straight and curved lines are similarly combined in regular or rhythmic relationships, so that while the alternation of these lines is esthetically pleasing and stimulating, the total effect is nevertheless restful because unifying. But when these combinations of unlike outlines are not repeated or echoed - as when a round or elliptical mirror is placed between the straight supports of a straight-lined dresser or hung above a rectangular wall table or cabinet, or when a circular pillow is used on a big straight-lined davenport - no element of likeness is present and the contrast stands out in sharp relief.