Graphics Programs Reference
In-Depth Information
CHAPTER 5
Building Camera Profiles
In Chapter 4, I discussed how scanners create RGB files, which require
an ICC profile to define the data for use within a color-managed envi-
ronment. Digital cameras are no different in this regard. A digital camera,
however, is a capture device that is quite different from a scanner. Scan-
ners are quite simple and consistent in how they record what is placed
in front of their sensors. Digital cameras have the entire visible world
before them that they attempt to reproduce, whereas scanners only need
to capture the colors and tone in film or prints. With digital cameras,
there are a multitude of settings and options—different lens and F-stops,
different illuminants, different tonal ranges—to try to capture a phe-
nomena known as metamerism (see the sidebar, “Metamerism”). This
makes producing a useful ICC profile a difficult, and some would say
impossible, task. The fact remains that we do need some descriptor for
the color files we get from these devices. Photoshop and other ICC-savvy
applications don't know when an image being viewed and edited comes
from a scanned piece of film or a digital camera.
Few debates among color experts and color geeks have been more
vocal than the effectiveness of profiling digital cameras. There seem to be
two groups of experts. One group suggests that making a profile from a
digital camera is fraught with issues and is at best a compromise. The
other group suggests that building one profile for a camera is not only
possible but also the best way to ensure color accuracy. Anything short
of a custom profile is a compromise.
My own experience in building camera profiles over the years, dating
back to what I believe was the first product to create digital camera pro-
files (a long-abandoned product from Heidelberg named
LinoColor Dcam
),
falls somewhere in the middle. This may be due, in part, to my split
Gemini personality. I have found that producing a usable camera profile
is often a hit or miss experience. Producing a custom ICC profile using
certain targets and certain software products on certain camera systems
would work beautifully, but other times, depending on any number of
variables, the results were heinous. The only viable solution was to have
as many camera profiling software products and color targets known to
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