Industrial Arts Design / A Textbook of Practical Methods for Students, Teachers, and Craftsmen

by William H. Varnum

Shades

Each standard hue may be darkened by the application of black, thus forming shades of that hue. Red is capable of producing two shades, R-D and R-LD, which are placed in the left boundary of the hue rectangle below the standard hue. Browns, russets, and dark tans are shades of different hues.

These modifications of the standard hues into tints and shades give to the designer simple variations of his too brilliant standards. But even these modifications are not sufficiently grayed for staining or painting large wood or wall surfaces. There is a brilliancy and glare about certain tints which require modification. The shades are safer for use on large areas. The remaining space in the interior of the hue rectangle is to be devoted to the last gradation of the standard hue.

Chroma

Chroma is the strength of a color. It is the quality by which we distinguish a strong color from a weak one. The standard hue is approximately full chromatic intensity. Likewise each tint and shade is considered to be of its full chromatic intensity, making the left-hand boundary of the rectangle the area of full chroma.

From this boundary, each tint, standard, and shade fades out or loses chroma until the right boundary of the rectangle is reached. In this boundary each tint, standard, and shade has faded out of its gray equivalent, but without changing its original value; in other words it has traveled along its horizontal value line to a complete grayness. The right-hand boundary of the rectangle may then be represented by a gray value scale of nine steps, including white and black.

Vertical Chroma Lines

It becomes necessary to record at regular intervals, this loss of chroma. For this purpose, we have cut the hue rectangle by three vertical lines. The first vertical line from the left boundary of the rectangle marks the position where the standard with its tints and shades have been grayed to the point where only three-fourths of the original of hue remains. Similarly, the center and right vertical lines mark the points where one-half and one-fourth, respectively, of the color have been retained. These losses of chroma are recorded by similar fractions. With possible modifications of value and chroma each hue now has twenty-seven possible changes.

Full Hue Symbols