Install a color profile
Color profiles are often installed when a device is added to your system. The accuracy of these profiles (often called generic profiles or canned profiles) varies from manufacturer to manufacturer. You can also obtain profiles from a custom profile service, download profiles from the web, or create custom profiles using professional profiling equipment.
* In Windows, right-click a profile and select Install Profile. Alternatively, copy the profiles into the WINDOWS\system32\spool\drivers\color folder (Windows XP).
* In Mac OS, copy profiles into the /Library/ColorSync/Profiles folder or the /Users/username/Library/ColorSync/Profiles folder.
After installing color profiles, be sure to restart Adobe applications.
About color management in Lightroom
Lightroom simplifies color management in your photographic workflow. You don’t need to choose color settings or color profiles until you are ready to output your photos. To take advantage of Lightroom color management, you need to calibrate your computer monitor so that you are viewing accurate color. See Calibrate and profile your monitor.
Color spaces, color profiles, and tonal response curves
It’s not necessary for you to understand how Lightroom manages color internally, but the following information may be useful in your workflow.
A color space describes a range or gamut of colors. Various devices in your photographic workflow have different color gamuts in which they can record, store, edit, and output photos. A color profile defines a color space so that Lightroom knows how to manage and convert colors in your photo.
Raw photo files generally don’t have embedded color profiles. For raw files, the Develop module assumes a wide color space based on the color values of the ProPhoto RGB color space. ProPhoto RGB encompasses most colors that cameras can record.
A color profile is also defined by a gamma value, or more accurately, its tonal response curve. The tonal response curve defines how tonal values in the raw image are mapped. To provide useful information in the histogram and RGB value display, Lightroom assumes a gamma value of approximately 2.2. More accurately, it uses a tonal response curve similar to the tonal response curve of the sRGB color space.
While Lightroom uses a tonal response curve to provide information for the histogram and RGB values, it manipulates the raw data before it is tone mapped. Working in this linear gamma avoids many of the artifacts that can result in working with a tone-mapped image.
The Library module stores Low and Medium quality previews in the Adobe RGB color space, and High quality previews in ProPhoto RGB. These previews are also used when printing in draft mode.
For rendered files such as TIFF, JPEG, and PSD files, Lightroom uses the image’s embedded color profile to display the image, histogram, and color values. If the image doesn’t have a profile, Lightroom assumes the sRGB profile, and the image may not look as expected on your monitor.
Output color profiles
When you print a photo in Lightroom, you can choose to convert the colors to more closely match the color space of the printer, paper, and ink you are using. For information on working with printer color profiles, see Set print color management.
Lightroom automatically exports images in the Slideshow and Web modules using the sRGB profile so that the color looks good on the majority of computer monitors.
Calibrate and profile your monitor
...more at http://help.adobe.com/en_US/Lightroom/2.0/WS268F3399-80B2-4169-A598-04C7F769FFA0.html#WSC7DFD470-BF58-4e3a-B038-14E4527437E1