All objects perceived by man, whether natural or artificial, are visible because of their color, and because of that alone. A thing is visible because it is darker or lighter than something beside or behind it or is of a different hue, and the shape of its color mass gives the idea of form. This form is often expressed by means of a line drawn with pencil, pen, or brush, though there is nothing in nature which really warrants the use of such a line, as everything is perceptible by masses, and these masses consist of varying amounts of different colors. The long-established conventions of drawing have enabled us to perceive the idea of objects when their outlines alone are represented, and this abstraction has given rise to what is termed "line-drawing," or drawing in outline. The imagination of the spectator, relying upon memory, fills in these outlines with the proper colors, and thus the drawing indicates reality. These outlines, however, are in themselves abstractions, and like nothing else in nature. In drawing processes, then, it is the color shape that is indicated by the drawn lines.

One element of color, dark and light, is perhaps most important in the perception of objects, and this darkness and lightness is known as value.

At night one does not perceive objects readily because the absence of light has minimized value contrasts, making the objects appear uniform in color, and where color differences are not perceived, individuality is lost. On a moonlight night the principal perceptions are of "values," -that is, lights and darks, - with other slightly differing color qualities added. The shadows are all a sort of deep violet black, and the "high-lights" a greenish yellow. Forms are consequently seen only in their larger relationships where they are relieved by shadow, but in the shadow itself all detail is lost, because there is insufficient light to make color distinctions.

Where the light conditions are such as to make colors easily perceptible, the color viewed abstractly is of more importance than the form, for it repels or attracts more readily than any other one element of design.

Color is divided into three parts, value, hue, and intensity, and into these parts any color may be finally analyzed.* Value, as has been said, is the lightness or darkness of a color, without taking into consideration the hue or intensity.

The hue of a color is its individuality, - the quality which gives it a name, such as red, blue, or green. Hue differentiates colors of the same value and intensity. Its gradations may be very slight; for instance, a number of colors may be chosen any one of which would unhesitatingly be pronounced "blue," and yet upon comparison it will be seen that no two are alike.

Figure 19. DIAGRAM OF COMPLEMENTARY COLORS

Figure 19. DIAGRAM OF COMPLEMENTARY COLORS.

* Cf. "A Text-Book of Design," Kelley and Mowll, pp. 106 et seq.

Color names, -unfortunately, are loosely applied, and the painters call hues by names which mean nothing to the dry-goods dealer who is evolving new colors (in name at least) every year to satisfy the demands of his fair patrons for something new. The horticulturists use a still different terminology, and, sad to relate, are rather careless about it, too. On account of the all-pervasive looseness in color characterization, it has seemed best to keep the color names in this book as simple and definite as possible.

Intensity is the brilliancy of a color, and its opposite may be called neutrality. Imagine two blossoms of the same hue, such as blue, for instance. They are of the same value; one is neither lighter nor darker than the other; one is a bright blue and the other is a dull blue, which is merely another way of saying that the intensities are different. The brighter flower has the greater intensity. A bright color in unfavorable surroundings is much more offensive than a dull one; consequently it is safer to use brilliant colors sparingly, relying on colors of less intensity for the greater part of the scheme. If a high intensity is characteristic of a planting scheme, it will be difficult to secure an accent color unless it is one of the highly specialized horticultural varieties, such as the Japanese maples and varicolored shrubs.

Among a number of brilliantly colored plants all clamoring for attention, an accent plant will have to be very powerful indeed in order to make its presence felt. Needless to say, a scheme of this sort is entirely out of place in everyday surroundings.

As a rule it is much more satisfactory to restrict the hues and intensities, using differing values for accent purposes, and leaving the color contrasts for unusual situations and effects.

Colors may be divided into two classes, the primary colors, red, yellow, and blue, from which all other colors are made, and the complementary colors, often called secondaries. Complementary colors are those which have nothing in common,-giving the greatest possible color contrasts. Every color has its complement in the color most unlike it.

The complement of any primary color is a secondary which is composed of equal visual amounts of the other two primaries. Conversely, every secondary color has as its complement the primary which does not enter into its composition. In the color cycle (Fig. 20) the complementary colors appear directly opposite one another. Red and yellow, mixed, give orange; yellow and blue, green; blue and red, purple or violet.

If complementary pigment colors are mixed in equal quantities, each kills or neutralizes the other, and the result is gray, in which neither of the complements is traceable. In fact, complementary colors are so antagonistic that they will neutralize one another if used in anywhere near equal quantities. On the other hand, they may be used together to great advantage if a very small amount of one is present. In this case there is no doubt as to which is the predominating color, and all its good qualities are set off to advantage by the presence of its complement, unlike it in every respect. Such arrangements are very stimulating.

Figure 20. DIAGRAM OF SEASONAL COLOR CHANGES

Figure 20. DIAGRAM OF SEASONAL COLOR CHANGES.