Each example on this plate may be made the basis of many variants, by small changes in the color steps, as suggested in the text, and further elaborated in Chapter VI. Indeed, the studies reproduced on Plates II. and III. are but a handful among hundreds of pleasing results produced in a single school.[26] 1. Pattern. Purple and green: the two united and thinned with water will give the ground. Vary with any other color pair. 2. Pattern. Figure in middle red, with darker blue-green accent. Ground of middle yellow, grayed with slight addition of the red and green. Vary with purple in place of blue-green. 3. Japanese teapot. Middle red, with background of lighter yellow and foreground of grayed middle yellow. 4. Variant on No. 3. Middle yellow, with slight addition of green. Foreground the same, with more red, and background of middle gray. 5. Group. Background of yellow-red, lighter vase in yellow-green, and darker vase of green, with slight addition of black. Vary by inversion of the colors in ground and darker vase. 6. Wall decoration. Frieze pattern made of cat-tails and leaves,--the leaves of blue-green with black, tails of yellow-red with black, and ground of the two colors united and thinned with water. Wall of blue-green, slightly grayed by additions of the two colors in the frieze. Dado could be a match of the cat-tails slightly grayer. _See Fig. 23, page 82._ 7. Group. Foreground in purple-blue, grayed with black. Vase of purple-red, and background in lighter yellow-red, grayed. For analysis of the groups and means of recording them, see Chapter III. [Footnote 26: The Pope School, Somerville, Mass.] CHAPTER V. A PIGMENT COLOR SPHERE.[27] +How to make a color sphere with pigments.+ (102) The preceding chapters have built up an ideal color solid, in which every sensation of color finds its place and is clearly named by its degree of hue, value, and chroma. [Illustration: Fig. 16.] It has been shown that the neutral centre of the system is a balancing point for all colors, that a line through this centre finds opposite colors which balance and complement each other; and we are now ready to make a practical application, carrying out these ideal relations of color as far as pigments will permit in a color sphere[27] (Fig. 16). [Footnote 27: Patented Jan. 9, 1900.] (103) The materials are quite simple. First a colorless globe, mounted so as to spin freely on its axis. Then a measured scale of value, specially devised for this purpose, obtained by the daylight photometer.[28] Next a set of carefully chosen pigments, whose reasonable permanence has been tested by long use, and which are prepared so that they will not glisten when spread on the surface of the globe, but give a uniformly mat surface. A glass palette, palette knife, and some fine brushes complete the list. [Footnote 28: See paragraph 65.]