Graphics Programs Reference
In-Depth Information
Don't necessarily fall into this hype, which says there are no wider spaces for print/output than
sRGB or that all you really need to do is supply sRGB and all your color management problems
will disappear.
Which Working Space?
There continue to be endless debates as to the best working space. What
we want in an RGB working space is a gamut that is sufficiently large
enough to contain all the colors our capture devices can produce as well
as having a gamut sufficiently large enough for all the output devices we
intend to use. That's a difficult gamut to gauge when you might have
multiple capture devices and output devices. There's little question that
printers and display systems might come onto the scene that have much
larger color gamuts than we currently have today. In fact, that's exactly
what is happening with newer display technologies. Is it a good idea to
use a working space that has a color gamut, which may restrict the colors
we hope to reproduce in the future?
This might lead you into believing a very large color gamut is ideal.
Since the container is so large, a wide gamut working space ensures we
have plenty of extra volume for the future. Who wants to have a 15-
gallon gas tank when a 30-gallon tank is available? The problems with
very large gamut working spaces are twofold. First, it's entirely possible
to have an RGB working space with a gamut that is significantly larger
than the gamut of the display we use to view our images. Users seem to
think their displays have the widest gamut possible but this is far from
the truth. This is why sRGB is so attractive to some. The sRGB gamut
isn't that much different than many low-end displays. When you have
an image that contains most or the entire available gamut found in Adobe
RGB (1998) some colors will be outside the display gamut. The problem
then becomes editing colors in the image that you can't see on the display.
For example, as you move a slider in Photoshop's Hue/Saturation dialog,
a slight movement may not appear to be changing the image. In reality,
the colors are indeed changing more than you wish since the colors being
affected are outside the gamut of the display. Only when the document
is output to an equally large gamut printer can you see this incorrect edit.
Therefore, a working space (and image) with a gamut that is much larger
than our display gamut can (and I want to stress can , not always will ) be
problematic.
The other problem with progressively larger color gamut working
spaces is they are not appropriate for editing images containing only 8-
bits per color channel. All 8-bit documents have to describe 256 levels
per color channel. A larger gamut color space means those colors are
farther apart than the same 256 levels in a smaller color gamut working
space. Very wide gamut working spaces like Wide Gamut RGB or
ProPhoto RGB are more appropriate for editing data that contains more
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