18 Color Standards and Nomenclature. 
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* are shown 
dulled by gradually increasing increments of neutral 
gray, the first (Plates XIII-XXVI, colors l'-7l') con¬ 
taining 32 per cent., the second (Plates XXVII- 
XXXVIII, colors l"-7l") 58 per cent., the third (Plates 
XXXIX-XLIV, colors l'"-69'") 77 per cent., the fourth 
(Plates XLV-F, colors l""-69"") 90 per cent., and the 
fifth (Plates Ll-kHI, colors l'"", 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 Fill) 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, each 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. 
