Graphics Programs Reference
In-Depth Information
Display Using Monitor Compensation
Adobe realized that all documents need embedded ICC profiles so that
the numbers could have a definition within the context of the color man-
agement system. We've seen that different numbers can produce the
same color appearance and identical numbers can have different color
appearances. The key to having the numbers within an image preview
correctly is having an ICC profile embedded (also known as tagged) in
each document that describes what the numbers actually represent!
Having documents with embedded profiles along with an ICC profile
for the display allows Photoshop to do something new and unique, a
process known as
Display Using Monitor Compensation
. What Display Using
Monitor Compensation does is to provide a mechanism that uniquely
compensates for each user's display using the ICC profile that describes
the unique behavior of that display. The display profile has all the rele-
vant information about the color behavior of this device-dependent
display. Even if the display condition is a bit too yellow, as long as the
ICC profile of the display accurately recognizes this, Display Using
Monitor Compensation alters the preview by adding the correct amount
of blue compensation. Display Using Monitor Compensation provides an
on-the-fly RGB conversion from the ICC profile of each document to the
device-dependent profile of the display using 20-bit precision.
This compensation is the key in producing matching color appearance
with the same set of numbers on a series of displays that are not identi-
cal. This is an impressive feature because it allows users to view docu-
ments on virtually any hardware and have all the images match,
assuming the document on each machine has an embedded profile
and each display is properly calibrated and profiled. Thanks to Display
Using Monitor Compensation, the various displays don't need to be
close in their actual behavior as long as those unique behaviors are
accurately described within the ICC profiles. My analogy of Display
Using Monitor Compensation would be that of a photographer who
had two batches of color film that produced slightly different color
appearances. By placing the right set of color correction filters over
the lens, a match between these two film emulsions can be achieved. In
the same way, Display Using Monitor Compensation is like a correction
filter that Photoshop uses to affect
only
the display, not the numbers
in the document. Users on different platforms might calibrate their dis-
plays to different TRC gamma settings. Since the ICC display profile
records this, the compensation on each machine would alter only the
preview so that both users see the same appearance from the same set
of numbers.
This ability to show the same color appearance on different displays
is due to the use of two ICC profiles: the embedded profile in the docu-
ment and the display profile. Many applications that can display color
images don't behave this way, and it is very common to hear users
