Adobe Illustrator CS4 - Manual (Page 137)

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Chapter 5: Color management
A color management system reconciles color differences among devices so that you can be reasonably certain of the
colors your system ultimately produces. Viewing color accurately allows you to make sound color decisions
throughout your workflow, from digital capture through final output. Color management also allows you to create
output based on ISO, SWOP, and Japan Color print production standards.
Understanding color management
Why colors sometimes don’t match
No device in a publishing system is capable of reproducing the full range of colors viewable to the human eye. Each
device operates within a specific color space that can produce a certain range, or gamut, of colors.
A color model determines the relationship between values, and the color space defines the absolute meaning of those
values as colors. Some color models (such as CIE L*a*b) have a fixed color space because they relate directly to the way
humans perceive color. These models are described as being device-independent. Other color models (RGB, HSL, HSB,
CMYK, and so forth) can have many different color spaces. Because these models vary with each associated color space
or device, they are described as being device-dependent.
Because of these varying color spaces, colors can shift in appearance as you transfer documents between different
devices. Color variations can result from differences in image sources; the way software applications define color; print
media (newsprint paper reproduces a smaller gamut than magazine-quality paper); and other natural variations, such
as manufacturing differences in monitors or monitor age.
Color gamuts of various devices and documents
A. Lab color space B. Documents (working space) C. Devices
What is a color management system?
Color-matching problems result from various devices and software using different color spaces. One solution is to
have a system that interprets and translates color accurately between devices. A color management system (CMS)
compares the color space in which a color was created to the color space in which the same color will be output, and
makes the necessary adjustments to represent the color as consistently as possible among different devices.
CMYK
RGB
A B
C