Table of Contents
Advertisement
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 manipu-
lates 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 previews in the Adobe RGB color space. 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" on page 118.
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
You can calibrate your monitor and create a profile that specifies its color characteristics using monitor profiling
software and hardware.
When you calibrate your monitor, you are adjusting it so that it conforms to a known specification. Once your
monitor is calibrated, the profiling utility lets you save a color profile.
If you are calibrating a CRT monitor, make sure it has been turned on for at least a half hour. This gives it sufficient
1
time to warm up and produce more consistent output.
Set the ambient lighting in your room to be consistent with the brightness and color of the room lighting you'll
2
be working under.
Make sure your monitor is displaying thousands of colors or more. Ideally, make sure it is displaying millions of
3
colors or 24-bit or higher.
Remove colorful background patterns on your monitor desktop, and set your desktop to display neutral grays.
4
Busy patterns or bright colors surrounding a document interfere with accurate color perception.
Calibrate and profile your monitor using third-party software and measuring devices. In general, using a
5
measuring device such as a colorimeter along with software can create more accurate profiles because an instrument
can measure the colors displayed on a monitor far more accurately than the human eye.
Note: Monitor performance changes and declines over time; recalibrate and profile your monitor every month or so. If
you find it difficult or impossible to calibrate your monitor to a standard, it may be too old and faded.
Most profiling software automatically assigns the new profile as the default monitor profile. For instructions on how
to manually assign the monitor profile, refer to your operating system's Help.
PHOTOSHOP LIGHTROOM
13
User Guide
Advertisement
Table of Contents
