In article ,
nospam wrote:

In article ], isw
wrote:

I have a large number of scanned slides bearing a color profile
(assigned by the scanner) that gives iPhoto fits; I'd like to change it.

iphoto does weird things with colour profiles. use something else if
possible.

Not possible. Plus, what I've been able to understand from reading about
iPhoto and profiles is that honoring profiles is a *good* thing for
color accuracy.

it's a very good thing, except iphoto doesn't quite do it right.

what profile did the scanner give it?

Microtek 4800 Scanner / Positive Film / Present

Why that annoys iPhoto I don't know, but the result is that when I
import an image bearing that profile, the thumbnail winds up being a
black rectangle. I suppose it's possible that there's some aspect of
that profile that is "wrong" somehow, but I have no way to fix it, so
just eliminating it seems like a good solution.

that's worse than i thought. usually the colours are a little off if
it's the wrong profile, not black.

there's a profile first aid check in color sync utility - what does
that say? what happens if you try other software, such as photoshop,
preview, or even safari?

ColorSync doesn't complain, nor do other apps, except to ask if it
should be converted. iPhoto displays the full-sale image just fine too;
it's just the thumbnail that's black. Real problem is, when I delete
those images so I can change the profile and reimport, then emptying the
iPhoto trash almost always causes a crash, and sometimes requires a
database rebuild, which takes several hours.

Ah. Then using "assign" to get rid of the problematical profile sounds
like a mistake, since the result would be that the profile would be
"lying" about the image. I'd guess you'd use "assign" if you knew what
an image's profile *should* be, but that's not what was in the metadata.

except if that profile is corrupt or the software you are using is
buggy. if another profile makes it look better, what difference does it
make? after all, that's what matters not what is technically 'correct.'
although the correct profile should be the one that looks the best,
that's not always the case.

I understand that, but I also *think* I understand that once an image
has been shoehorned into a limited color gamut, there's no way to
recover what's been lost.

Now, what is a good profile to move to, assuming I want the widest
reasonable color gamut on CRT or flat-panel displays but NOT involving
the web or browsers? (What I mean is, showing my images to friends and
relatives on a computer or digital TV).

for showing on a screen, srgb is probably fine. do your friends have
expensive eizo lcd displays that can display adobe rgb? probably not.
if their displays can only show srgb, why bother using something wider?

Because I expect that in future, even commodity displays are going to
have a wider gamut than present-day high-end ones; don't you?

I *think* I understand that sRGB is a rather limited gamut, for example.
What about ProPhoto? Using colorSync Utility, it seems to be nearly the
only gamut that's larger than the scanner's.

srgb is fine for most things, but if you really want to edge out the
absolute best, you want adobe rgb or better, however, once it's
scanned, you aren't going to gain much by picking a wider space.

According to ColorSync Utility, the existing profile (Microtek 4800
Scanner), is considerably larger then either sRGB or AdobeRGB, but
smaller than ProPhoto. What I'm interested in, is not throwing anything
away that might be valuable later, say on next-generation displays.
These are family images I'm preparing for my kids; they may well be
viewed in 50 years or more.

Isaac