Which Working Space Should I Use?
Your choice of working space will determine
the colors that are available as you edit,
and ultimately output, your image. A working
space's range of colors is its gamut. Your
goal is to match your working space gamut
to the gamut of your output device.
You can let Photoshop make the working space
decision for you by selecting one of the
predefined color management settings from
the Settings drop down shown in Figure 2.
For many users, these predefined sets will
work just fine.
Figure
2: Settings drop-down with
predefined settings showing.
Don't be fooled by the "Color Management
Off" selection under Settings. This
particular set of predefined color management
settings sets the RGB workspace to your default
monitor profile, generally not a good choice
for most users. More about these predefined
settings below.
Alternately, you can make your own combination
of Color Settings by selecting Custom from
the Settings drop down and saving your selections
with the Save... button. These custom settings
files can be shared by multiple users and
by other Adobe programs like Illustrator
and InDesign.
Most of the predefined settings will select
either Adobe RGB(1998) or sRGB IEC61966-21
for your RGB working space. Macintosh users
have a predefined setting choice, ColorSync
Workflow, that accesses the preferences made
in the ColorSync dialog and the Monitors
Control Panel, and keeps you from having
to repeat your selections in the Color Settings
dialog.
The standard RGB choices for a PC are shown
in Figure 3.
Figure
3: RGB Working Spaces drop-down
selection list.
Most users will end up in either Adobe RGB
or sRGB. In general terms, Adobe RGB has
a larger gamut than sRGB, and allows you
to work in more saturated color (not more
colors) than sRGB. Adobe RGB more closely
matches the color gamut of photo quality
color printers. It is a good choice for those
users working in RGB with output going to
print, either as RGB files for photo quality
inkjet printers, or, after conversion, as
CMYK files for offset printers. sRGB, with
its smaller color gamut, is intended to match
the characteristics of the average PC monitor.
It is a good choice for images going to the
web and for images going to color printers
with limited color capabilities.
Other Adobe supplied working spaces include
Apple RGB, which reflects the characteristics
of the average Macintosh monitor, and ColorMatch
RGB, which matches the color space of the
Radius Pressview monitor. ColorMatch RGB
has a smaller gamut than Adobe RGB, but has
been long used as a standard for prepress
work in the publishing industry.
All of these Adobe supplied working spaces
map the characteristics of various output
devices with limited gamut ranges, either
printers or monitors. Embedding one of these
profiles in an image with a wide gamut, say
a raw scan from a scanner capable of capturing
a wide gamut from color film, will force
the wider gamut into the smaller gamut space
by clipping or converting pixel data. This
implies that you should save copies of any
wide gamut images before allowing Photoshop
to embed a working space and losing the wider
gamut information from the file.
Incidentally, one important characteristic
of all these RGB working spaces is their
ability to form a neutral gray with equal
values of red, green, and blue. This becomes
an important feature when color correcting
images.
You also have the option of either importing
other RGB working spaces or creating your
own custom working spaces. Import RGB spaces
by selecting Load RGB... under the RGB drop
down menu in the Color Settings dialog and
then selecting an icc/icm file. Create a
new RGB workspace by selecting Custom RGB...
and entering the requested data in the Custom
RGB dialog.
Continued: Page 
Copyright 2002 Michael W. Rollins
