Page:Elementary Color (IA gri c00033125012656167).djvu/78

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68
PRACTICAL EXPERIMENTS.

several papers ready made this harmony becomes very simple, hut in the use of pigments the production of a true color scale is not a thing to be confidently undertaken by a novice.

In a very elaborate color chart for Primary education prepared with great care by Dr. Hugo Magnus and Prof. B. Joy Jeffries, and published at large expense about ten years ago with hand-painted samples in oil colors, this lack of classification of hues is very noticeable, although at that time it was by far the best publication of the kind and was not criticised on this point.

For example in a scale of five tones of red the following are the analyses, beginning at the lightest tint: —

  • Tint No. 2, O.45, Y.20, W.18, N.17.
  • Tint No. 1, O.69, Y.3, W.7, N.21.
  • Standard, R.75, O.25.
  • Shade No. 1, R.85, O.15.
  • Shade No. 2, R.75, N.25.

In this scale according to the Bradley nomenclature the standard or full color is a very fine vermilion expressed by R.75, O.25, i. e. an orange red, and therefore in order to form a perfect scale both tints and shades should be in the orange reels, but in fact the tints are both broken colors, the lightest a very broken yellow-orange and the deeper tint very nearly a light broken orange. The lightest shade is a pure orange-red but with a larger proportion of red to the orange than the standard, while the darkest tone is a pure shade of red. Thus in the five tones we have the following arrangement, beginning at the lightest tint:—

Broken yellow-orange, broken orange, orange-red; another pure orange-red but more red, and lastly red shade, thus embracing in one orange-red scale parts of four scales from yellow-orange to red. In these defects in the best chart of its kind in the market only ten years ago is seen the best possible evidence of the advance made since that time in color perception, largely due to the use of the color disks in determining scales.