Graphics Programs Reference
In-Depth Information
than 8-bits per color—what Photoshop considers 16-bit color. The editing
in 16-bit data will allow smooth transitions and a lack of banding com-
pared to an 8-bit file in the same gamut working space. However, the
colors that are severely outside of display gamut are still invisible to the
user.
We should examine the role of the output devices in the imaging
chain when evaluating an RGB working space. The ideal working space
is one that, if possible, can fully contain the entire gamut for printing,
assuming again that we know each and every output device we wish to
print to, today and in the future. The type of imagery will certainly play
a role. If an image has highly saturated colors that we hope to reproduce,
a larger gamut working space certainly can play a bigger role than if the
image contains only pastel colors. Having a smaller gamut color space
will not ensure poor output. However, there may be some colors that we
might wish to reproduce that we cannot due to the gamut of the working
space. This really isn't necessarily anything to lose sleep over but it's a
consideration that you should be aware of. Many people produce beau-
tiful images with working spaces that have a gamut that is smaller than
the capture devices or resulting print/output space. In Chapter 9, Tutor-
ial #4: “RGB Working Spaces,” you will work with a supplied, saturated
test image (as well as your own files) to convert to a number of standard
RGB working spaces and then print to your preferred output device. This
is the best way to get a feel for what happens to imagery that contains a
wide gamut of colors and the effect of the various working spaces on the
colors in such a test file.
Many find that Adobe RGB 1998 is one of the better choices for an
RGB working space. Adobe RGB 1998 has a gamut that fully contains
the typical CMYK print gamut. The gamut of this space is a bit larger than
the typical monitor but not by an amount that should be a concern. In
fact, several new display technologies are addressing this need for wider
gamut to allow for such working spaces. The Mitsubishi RDF225WG has
a new phosphor set that contains 98 percent of the Adobe RGB 1998
gamut. Figure 2-1 shows the gamut map of this display compared to other
more typical displays. Other wide gamut display technologies that are
close to the full Adobe RGB 1998 gamut are coming to market as well.
Those who intend to print to continuous tone printers (Lightjet, Lambda,
etc.) as well as most ink-jet printers will find that Adobe RGB 1998 con-
tains a sufficient gamut for these printers. For those who need to output
files to a film recorder, a much wider space might be necessary, again
depending on the imagery and the source of the color data. We need a
capture device that has a sufficiently large gamut to begin with and many
such devices exist. Note that when comparing the gamut of the display,
printer, and the working space, some areas in one space may be larger
in gamut in one area but smaller in another. The issue then becomes a
gamut mismatch between the various devices. This isn't necessarily some-
thing to be concerned with.
