CHAPTER 2: Understanding Key Color Management Concepts
Device Profiles
Once you calibrate a device, you’ll then want to create a
pro le that describes the devices range of color and tone in
its calibrated state. These device pro les can communicate
with other device pro les in a color-managed work ow to
increase the consistency of results.
Output Pro les
An output pro le is a characterization of
the range of colors that a speci c printing
device and paper type reproduces.
To create an output pro le, a variety
of color patches must be printed and
measured with a device known as a
spectrophotometer. The next step is to
enter the data from the patches into a
software-pro ling application to create
an ICC pro le. The software compares the
known color values of the patches sent
to the printer to the actual colors that
were read with the spectrophotometer
and, using the data from that
comparison, creates an ICC pro le.
Monitor Pro les
A monitor pro le is created during the
calibration process with a device known
as a colorimeter, which compares the
values and colors that it reads to a
known set of values and colors. The
monitor pro le (also known as the system
pro le) will serve as a viewing  lter,
allowing you to see your image data
more accurately. The dynamic range, or
contrast levels, of the monitor is limited
by the maximum brightness that it has.
Newer LCD monitors are usually brighter
than older CRT monitors, and are thus
capable of a wider dynamic range.
The Xrite Pulse Elite, a color spectrophotometer
ETCM_book.indb 12 10/6/06 4:30:21 PM
Input Pro les
Because scanners and digital cameras
don’t have a  xed gamut (see the next
section, Color Space”), input pro les
for these devices are a little bit di erent
than output and monitor pro les.
Input pro les do, however, have a  xed
dynamic range. So an input pro le can
characterize a device, but it is limited
to the target that you use to create the
pro le. With scanners, this limitation is
usually not a problem because you can
make a target with a dynamic range and
gamut of colors as good as any image
that you would scan. A digital camera,
on the other hand, captures colors in the
real world much better than any target
that could be made. The camera-pro ling
software has to extrapolate the colors that
are outside the target’s gamut. For this
reason, pro ling digital cameras is limited.
Matrix and LUT Pro les
Pro les themselves can be matrix-based
or LUT (lookup table)-based, both of
which include the white point of the
device. But matrix-based pro les are
very small, while LUT pro les are much
larger and more complex. A matrix
pro le is a mathematical model made
up of the three primary colorants of the
device and some simple tonal curves,
referred to as a 3 x 3 matrix. A LUT-based
pro le contains much more information,
consisting of a table of numbers that
allows you to  nd an input value and
its corresponding output value. Matrix-
based pro les are used for simpler
devices, such as scanners and monitors,
while LUT-based pro les are used for
more complex devices, such as printers.
GretagMacbeth Color Checker SG
An IT-8 chart
Device Profiles
ETCM_book.indb 13 10/6/06 4:30:41 PM

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