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Graphic Communications
Copyright Goodheart-Willcox Co., Inc.
The number of pure chromatic and achromatic
colors is small compared to all color possibilities.
The human eye can differentiate about 300 colors
and about 150 shades of gray.
Hue, Saturation,
and Brightness (HSB)
It is impossible to definitively describe the
appearance of a color. However, it is possible
to describe a color’s appearance in relationship
to its environment. The eye differentiates colors
according to the three basic criteria of every
color: hue, saturation, and brightness (HSB).
Together, these three characteristics define the
relationship between colors in the HSB color model,
Figure 11-14.
Hue is the color of an object perceived by
the eye, determined by the dominant light
wavelengths that are reflected or transmitted.
It is the color in its purest form as it sits on the
edge of the color wheel.
Saturation defines a color’s degree of strength
or difference from white. It can also be defined
as the predominance of one or two of the three
RGB primary colors.
Brightness is often referred to as lightness or
luminosity. The associated value indicates how
light or dark a color is.
Hue, Value, and Chroma (HVC)
In the early 1900s, Albert H. Munsell developed
a color organization and definition system based on
human perception. The Munsell system identifies the
three attributes of color as hue, value, and chroma
(HVC). In Munsell’s system, chroma indicates the
intensity, or strength, of a color and its saturation,
Figure 11-15.
Hue is the color name and is indicated by the
letter H, followed by a fraction. The top number
of the fraction represents the value. The bottom
number indicates the chroma.
Value is the lightness or darkness of a color.
It is shown on the central axis of the Munsell
model as nine visible steps. The darkest value
is at the bottom and the lightest value is at the
top. The value of pure black is designated as 0/,
pure white as 10/, and middle gray as 5/.
Chroma is shown by the horizontal band
extending outward from the value axis. The
chroma value shows the amount that a given
hue deviates from a neutral gray of the same
value. The number of chroma steps varies
because hues vary in saturation strength.
Munsell’s color system continues to be
popular in the fine arts area because it separates
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Figure 11-15. Hue, tint, tone, and shade are all defined in
this image according to the Munsell system.
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Figure 11-14. The HSB diagram showing hue, saturation,
and brightness.
Brightness
Hue
Saturatiion Sa Sa Sa S S S Sa Sa S S a S a tu tu t tu tu tu u ra ra ra a ra ra a a t ti ti ti ti o o on n o o n o on o on on n n
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