Digital visualization software offers a variety of color
environments to suit the needs of illustrators and designers. Each environment
has its own purpose and uses. Most of us are quite familiar with the color
spaces we use. Still, a basic understanding of all of the color options can be
useful.
RGB (The Monitor Model)
The RGB color model is composed of the primary colors
of red, green, and blue. The model, also known as the transmitted model, is an
additive color system. Color systems are classified by how the primary colors
relate to white. An additive system means that when all three primary colors
are added they create white. When
two of the primary colors are combined they produce a secondary color. In the
RGB system the secondary colors are cyan, magenta and yellow. Color monitors
and digital projectors use the RGB system to display color. According to the
trichromatic, Young-Helmholtz theory of color vision, the RGB color system
aligns very closely to the way the human eye processes color.
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| RGB color model. © 2012 Don Arday. |
CMYK (The Print Model)
CMYK stands for cyan, magenta, yellow, and black. Not
to be confused with the “B” in RGB, black is represented by “K”. Also referred
to as a reflective model, the CMYK system is a subtractive color system. When
CMY are combined they create black. White is produced by the total lack of
color and a white paper surface. When two of the primary colors are combined
they produce a secondary color. In the CMYK system the secondary colors are
red, green and blue. This alignment creates compatibility between the CMYK and
RGB systems when creating work for print output on a monitor system.
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| CMYK color model. © 2012 Don Arday. |
HSV (The Color Theory Model)
HSV is the acronym for hue, saturation and value. This
color model is also called HSB or hue, saturation and brightness; and HSL or
hue, saturation, and lightness. Very familiar to illustrators, the HSV model is
based on standard artists color theory. Although not specifically relating to
display hardware or printing equipment, it is an available color model in many
image software programs as a more intuitive system for use by artists.
The “hue” is a color. For instance, the color of sky on a clear day is a blue
hue. Every color is a hue.
The “saturation”, also called chroma, is a variation in
intensity of a color. It is the amount of grey proportionate to the hue. Saturation
can be used to alter a hue.
The “value” is the amount of lightness or darkness in a
color. Brightness can also be used to alter a hue.
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| HSV color model. © 2012 Don Arday. |
Lab (The Color Opposition Model)
Lab is an acronym. The “L” stands for lightness; the
“a” signifies the range of opposition between green and magenta; and the “b”
signifies the range of opposition between blue and yellow. Starting at a
neutral center greens are negative values while magentas are positive values.
Similarly, blues are negative values and yellows are positive values. This
complimentary color concept should seem familiar to illustrators and designers.
A simpler way to understand Lab color is to think of warm colors as positives
and cool colors as negatives. The type of Lab color used in computing is the
CIELab model. The CIE stands for the International
Commission on Illumination. The Lab system is based on the Munsell color
system. Basically, the Lab and Munsell color spaces are extruded 3D versions of
the familiar “color wheel”. Although an excellent model for helping artists to
understand color, the Lab system is not as compatible as RGB or HSV for use on
monitors or in software programming due to its complexity. The next time you
are working with an image in Photoshop, switch over to the Lab color space just
to see how surprisingly different the colors in your image appear.
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| Lab color model. © 2012 Don Arday. |
Grayscale (The Luminosity Model)
The Grayscale model is simply a range of tones between
black and none or white. The range in the grayscale model used by Adobe
contains 255 shades of gray plus white, and it is an 8-bit mode.
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| Grayscale color model. © 2012 Don Arday. |
Indexed Color (The Color Compression Model)
Like the 8-bit Grayscale model, an Indexed Color model
is limited to a finite index of colors. There are several Indexed Color models
in common use, including a 16 Color model, the PhotoImpact Optimization
Palette, the Graphics Interchange Format palette, and
others. The Standard Web Browser Palette with its limit of 216 colors is an
Indexed Color model. The Index color space in Adobe Photoshop is limited to 256
colors. In the case of the Photoshop Indexed Color space, colors in a
non-indexed color image are altered to match the 256 colors available. To
achieve this each pixel color is shifted to the nearest color in the color
palette and then dithered with similar colors to optically mix the
non-available colors.
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ANPA (American Newspaper Publishers Association) index of color
swatches. |
