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103
Adobe Photoshop Help
Producing Consistent Color (Photoshop)
Using Help
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Contents
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Index
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103
Color management engine
Different companies have developed various ways to
manage color. To provide you with a choice, a color management system lets you choose a
color management engine
that represents the approach you want to use. Sometimes called
the
color management module (CMM)
, the color management engine is the part of the
CMS that does the work of reading and translating colors between different color spaces.
Color numbers
Each pixel in an image document has a set of
color numbers
that describe
the pixel’s location in a particular color mode—for example, red, green, and blue values for
the RGB mode. However, the actual appearance of the pixel may vary when output or
displayed on different devices, because each device has a particular way of translating the
raw numbers into visual color. (See
“Why colors sometimes don’t match” on page 102
.)
When you apply color and tonal adjustments or convert a document to a different color
space, you are changing the document’s color numbers.
Color profiles
An ICC workflow uses
color profiles
to determine how color numbers in a
document translate to actual color appearances. A profile systematically describes how
color numbers map to a particular color space, usually that of a device such as a scanner,
printer, or monitor. By associating, or
tagging,
a document with a color
profile, you provide
a definition of actual color appearances in the document; changing the associated profile
changes the color appearances. (For information on displaying the current profile name in
the status bar, see
“Displaying file and image information” on page 48
.) Documents
without associated profiles are known as
untagged
and contain only raw color numbers.
When working with untagged documents, Photoshop uses the current working space
profile to display and edit colors. (See
“About working spaces” on page 106
.)
Do you need color management?
Use the following guidelines to determine whether or not you need to use color
management:
•
You might not need color management if your production process is tightly controlled
for one medium only, for example, if you’re using a closed system where all devices are
calibrated to the same specifications. You or your prepress service provider may prefer
to tailor CMYK images and specify color values for a known, specific set of printing
conditions.
•
You also might not need color management if you are producing images for the Web or
other screen-based output, since you cannot control the color management settings of
monitors displaying your final output. It is helpful, however, to use the Web Graphics
Defaults setting when preparing such images, because this setting reflects the average
RGB space of many monitors. (See
“Using predefined color management settings” on
page 105
.)
•
You can benefit from color management if you have more variables in your production
process (for example, if you’re using an open system with multiple platforms and
multiple devices from different manufacturers). Color management is recommended if
you anticipate reusing color graphics for print and online media, if you manage
multiple workstations, or if you plan to print to different domestic and international
presses. If you decide to use color management, consult with your production
partners—such as graphic artists and prepress service providers—to ensure that all
aspects of your color management workflow integrate seamlessly with theirs.
