Color Management and Why We Need It - Color Management for Photographers - page 30

Generic versus Custom Profiles
Virtually every device behaves differently, even if that device can be cal-
ibrated to some baseline specification. For example, the Fuji Pictrography
self-calibrated to factory specifications. Imagine making a profile for a
single Pictrography and having that profile work on all Pictrography
units. Fuji, like many manufacturers, supplies an ICC profile for their
Pictrography units. Although this profile is supposed to work with all
Pictrography devices, the truth is, there are enough variations between
devices that for best results, custom-made profiles for each unit are
preferable.
Epson supplies device profiles for its printers and papers. Like the Fuji
printer (and many others), this profile can do a reasonably good job, yet
the profile doesn't accurately describe every printer made. When a man-
ufacturer supplies a profile for their device, it is often called a canned or
generic profile . The manufacturer will sample a group of devices and often
will average the measured data to produce a profile in an attempt to
reflect average behavior of that particular make and model. If we were
to build a profile for a specific device and compare it to the canned profile,
we usually would find differences despite any calibration process we
might first conduct. My analogy is that of a man buying a suit off the
rack versus having a suit custom-tailored. The suit off the rack might be
perfectly acceptable and is certainly more affordable than a custom-made
suit. However, a custom-made suit does feel and look better. The same
is true with profiles. It is for this very reason I devote a good deal of this
topic to the tools that allow the creation of custom profiles.
Color Gamut
Another factor that makes color management a necessity with digital
images is something called color gamut . To explain color gamut using one
of my favorite (and oldest) analogies, we need to travel back in time
when I was a mere boy. My father bought me an impressively large box
of crayons containing some 200 colors. The next day, I was shocked to
find that my boyhood chum, Donny, had the 500-count box of crayons
with the very cool and useful built-in crayon sharpener. Donny's box of
crayons contained a bigger range of colors available for creating his
artwork. He had a larger color gamut than my puny box of just 200
colors. Thus, color gamut became an issue in my life, along with years of
therapy.
Back to the twenty-first century. Color gamut is simply a term that
describes the range of colors a particular device is able to reproduce.
Although people often use color gamut to describe all devices, it is best
used when discussing output devices like printers and display systems.
Input devices such as scanners and digital cameras technically don't have
a color gamut per say, but may be limited in what they can see. There is