On Jun 1, 2005, at 6:22 AM, Jón A Sandholt wrote:
This is a very interesting discussion, wich I have
been following
with great interest.
I have a question that relates to this topic.
How does bit depth ( 8 bit vs 16 bit etc.) relate to all this.We
are told that 8 bit color can give us about 16,7 million colors and
16 bit something much more (I don't wont even try to do the
calculations).I know this is only in theory but lets say you have a
8 bit image in ProPhoto RGB and one thats 16 bit in the same
colorspace, is there a difference between them as to how much part
of the space they use?
What I'm trying to say is does a high bit image make a better use
of a large colorspace than the 8 bit one?
Am I missing some point here or misunderstanding something?
Bruce has said a number of times on various lists and to me as well
that Prophoto RGB 8-bit/channel images can take more abuse than one
might suspect. I don't have an anecdote or rule of thumb really, to
indicate when there would be a problem. There are two schools of
thought: a.) work in 8-bits/channel until you have a problem that's
related to bit-depth then start over in 16-bits/channel; b.) work in
16-bits/channel even though a fair majority of the time there may be
no point in doing so.
It really depends on what kind of work you do, what kind of edits you
do, what's in the image (gradients of course are more susceptible to
posterization than noisy areas), etc.
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
-------------------------------------------------------------
Co-author "Real World Color Management, 2nd Edition"
Published by PeachPit Press (ISBN 0-321-26722-2)