tone scale, on the plates running vertically, growing from the full color, in the center, to a pale tint (at the top) and a dark shade (at the bottom). For clearer comprehension of these two distinct scales, each plate of this work may be compared to a sheet of woven fabric; the chromatic scale (horizontal) representing the warp, the luminosity or tone scale (vertical) the woof. A third kind of color scale is represented by adding progressive increments of neutral gray to any color. This is shown by the several series of Plates, of which the first (Plates I-XII, with colors numbered 1-71) represents each step in the spectrum scale unmixed with gray, followed by five other series in which the same colors[1] are shown dulled by gradually increasing increments of neutral gray, the first (Plates XIII-XXVI, colors 1′-71′) containing 32 per cent., the second (Plates XXVII-XXXVIII, colors 1′′-71′′) 58 per cent., the third (Plates XXXIX-XLIV, colors 1′′′-69′′′) 77 per cent., the fourth (Plates XLV-L,, colors 1′′′′′-69′′′′) 90 percent., and the fifth (Plates LI-L,III, colors 1 , 15 , 23′′′′′, 35 , 49′′′′′, 59′′′′′ and 67′′′′′) 95.5 per cent, of gray, the last being in reality colored grays. Finally scales are shown (on Plate L,III) of neutral gray (in which all trace of color is wanting), and of carbon gray, a simple mixture of lamp-black and Chinese white. It is not easy to find a suitable name for these scales of reduced or "broken" colors, but they may, for present convenience, be termed reduced or broken scales.
Full Color.—A color corresponding in intensity with its manifestation in the solar spectrum.
- ↑ The distinctions of color or hue diminishing in proportion to the increased admixture of gray, cadi alternate color or hue, with its scale (vertical) of tones, is omitted from the third and fourth series ; while in the fifth the color differentiation is so greatly reduced that only the six spectrum colors (dulled by admixture of 95.5 per cent, of neutral gray), together with purple (the intermediate between violet and red) are given; a yellow orange hue being substituted for spectrum orange because it is more exactly intermediate in hue between red and yellow.
