SkyRaider DS10CTEC User Manual
March 17, 2019
SkyRaider DS10CTEC User Manual
Page 78
CMYK
HSI
HLS
The
CMYK
mode is based on the light-absorbing quality of ink
printed on papers. As white light strikes translucent inks, certain
visible wavelengths are absorbed while others are reflected
back to the eyes.
In theory, pure cyan (
C
), magenta (
M
), and yellow (
Y
) pigments
should combine to absorb all light and produce black. For this
reason, these colors are called subtractive colors. Because all
printing inks contain some impurities, these three inks actually
produce a muddy brown and must be combined with black (
K
)
ink to produce a true black. (
K
is used instead of
B
to avoid
confusion with blue.) Combining these inks to reproduce color is
called four-color process printing.
The subtractive (
CMY
) and additive (
RGB
) colors are
complementary colors. Each pair of subtractive colors creates
an additive color, and vice versa.
Based on the human perception of color, the
HIS
model
describes three fundamental characteristics of colors:
Hue
is the color reflected from or transmitted through an object.
It is measured as a location on the standard color wheel,
expressed as a degree between 0° and 360°. In common use,
Hue is identified by the name of the color such as red, orange,
or green.
Saturation
, sometimes called Chroma, is the strength or purity of
the color. Saturation represents the amount of gray in proportion
to the hue, measured as a percentage from 0% (gray) to 100%
(fully saturated). On the standard color wheel, Saturation
increases from the center to the edge.
Intensity
is the relative lightness or darkness of the color, usually
measured as a percentage from 0% (black) to 100% (white).
The
HLS
model is very similar to the
HSI
color model. The main
difference between them is the calculation used to produce
the brightness value. In the HLS model, a pixel's brightness (
L
) is
derived from its three (R, G and B) color values. That is, a pixel's
brightness (
L
) is determined by the minimum and maximum
values of its three-color values.
