e" should be applied only to
darkened values, and not to hues or chromas. Yet one writer says, "This
yellow shades into green," which is certainly a change of hue, and then
speaks of "a brighter shade" in spite of his evident intention to
suggest a stronger chroma, which is neither a shade nor brighter
luminosity.

Children gain wrong notions of "tint and shade" from the so-called
standard colors shown to them, which present "tints" of red and blue
much darker than the "shades" of yellow. This is bewildering, and, like
their elders, they soon drop into the loose habit of calling any degree
of color-strength or color-light a "shade." _Value_ is a better term to
describe the light which color reflects to the eye, and all color
values, light or dark, are measured by the _value-scale_.

"Tone" is used in a confusing way to mean different things. Thus in the
same sentence we see it refers to a single touch of the brush,--which is
not a tone, but a paint spot,--and then we read that the "tone of the
canvas is golden." This cannot mean that each paint spot is the color of
gold, but is intended to suggest that the various objects depicted seem
enveloped in a yellow atmosphere. Tone is, in fact, a musical term
appropriate to sound, but out of place in color. It seems better to call
the brush touch a _color-spot_: then the result of an harmonious
relation between all the spots is _color-envelope_, or, as in Rood, "the
chromatic composition."

"Intensity" is a misleading term, if chroma be intended, for it depends
on the relative light of spectral hues. It is a degree rather than a
quality, as appears in the expressions, intense heat, light,
sound,--intensity of stimulus and reaction. Being a degree of many
qualities, it should not be used to describe the quality itself. The
word becomes especially unfit when used to describe two very different
phases of a color,--as its intense illumination, where the chroma is
greatly weakened, and the strongest chroma which is found in a much
lower value. "Purity" is also to be avoided in speaking of pigments, for
not one of our pigments represents a single pure ray of the spectrum.

Examples are constantly found of the mental blur caused by such
unfortunate terms, and, since misunderstanding becomes impossible with
measured degrees of hue, value, and chroma, it seems only a question of
time when they will take the place of tint, tone, shade, purity and
intensity.

CHAPTER II.

CO