Page:Color standards and color nomenclature (Ridgway, 1912).djvu/39

 TABLE SHOWING PERCENTAGE OF WHITE AND BLACK, RESPECTIVELY, IN EACH TONE OF THE TONE OR LUMINOSITY SCALES.

All of the vertical scales in the original Plates of this work (the scale of carbon grays alone excepted) contain the following percentages by color-wheel measurement:

One of the most serious difficulties encountered in the preparation of the Plates of this work was the apparent impracticability of reproducing satisfactory shades of pure colors. This originated in the fact that there seems to be no substance (pigment, dye, or fabric) which represents a true black, all reflecting more or less of white light, and consequently producing shades which are dull