There's an EXIF field stored in digital camera images as a 0 or a 1,
one of which meaning "sRGB" and the other meaning "other". It's
pretty vague, and I think not a great idea to begin with, but there it
is.
It's a fantastic idea, the problem is that the camera vendors don't
really render images into sRGB very well, which means sRGB often isn't
the best true source profile for image viewing and editing (for
printing directly to a printer without a desktop machine, it's a
different story which often does a better job than using a desktop
machine with default settings).
Color me crazy but what seems to be happening is iPhoto is ignoring the
EXIF tag, in favor of Monitor RGB (not Generic RGB, nor Camera RGB).
And yet if I had used Image Capture to grab that same file directly
from the camera, it would have favored "Camera RGB" which is a profile
using Generic RGB primaries and a 2.2 gamma.
Ignoring an implied sRGB tag wholesale without giving the end user an
option (and ignoring it in favor of two or three different profiles
depending on which Apple application touches it), is just as bad as
ignoring an embedded ICC profile. Both are metadata, and just because
Apple dislikes this particular kind of metadata doesn't mean it's
appropriate to always ignore it in every situation. The problem is then
compounded substantially by assuming a different source profile in
favor of it in different situations. It doesn't seem at all rational to
me, but if there's a good explanation I'd like to hear it.
When Photoshop sees that value it tells you there's an sRGB profile
in the image, which is unfortunate because it'll tell you the same
thing whether there's a real profile in there or just the EXIF field.
No. When there is an ICC profile embedded in the file, Photoshop uses
that profile and ignores the EXIF colorspace tag.
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)
