On Jun 1, 2005, at 1:37 AM, Karsten Krüger wrote:
Using ProPhoto RGB leaves you with just one choice of
color rendering:
colorimetric. If you are using photographic rendering your resulting
image will be very small compared to any other RGB colorspace.
Why would that be? I've had few problems with perceptual rendering with
ProPhoto RGB as source, even compared to sRGB.
But colorimetric rendering is often not sufficient,
because there are
likely out of gamut colors in digital photography (i.e. in blue
tones).
There is a possibility that you'd have sufficiently out of gamut colors
to fluxor the gamut compression built into relative colorimetric
rendering. But in practice, real images, not synthetic ones, take up a
small portion of ProPhoto RGB, so this ends up not being a problem.
An other drawback of ProPhoto RGB is that you will
hardly find a
monitor that is able to reproduce the whole colorspace. So you end up
editing data you are not able to see on your monitor and not able to
print out later...
While this is true, in practice I don't find it to be much of a
problem, again because the amount of ProPhoto RGB filled by the image
is comparatively small. There is logic in selecting an editing space
that is going to require clipping of colors for some workflows, but one
has to realize that this is throwing away data even before it's viewed
or edited. I for one don't want to relegate my images to the lowest
common denominator device in my image editing workflow - the display.
Especially as technology improves with wider gamut displays, and very
soon we will be seeing HDR displays as well, which means some issues
with respect to the ICC and how that's going to be handled.
Ideally I'd like to see us using a perversely enormous source space for
editing and archiving our images, and to see color management improve
so that it can better gamut map our images into the limited spaces we
have to live with for viewing, as well as printing. I remain skeptical
of clobbering images from the get go, in particular shadow detail much
of which can be reproduced in print but does not exist in smaller gamut
editing spaces. Really what we have here, with this religious debate
about editing spaces, is a hack because color management today is
unsophisticated enough to do a better job without us resorting to
faking out the CMS so it will do a better job than it can currently do.
ICC v4 brings us a little bit farther, but there needs to be more
widespread adoption, and I'd like to see some compelling results that
take full advantage of v4.
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
---------------------------------------------------------
Co-author "Real World Color Management, 2nd Ed"
Published by PeachPit Press (ISBN 0-321-26722-2)