Re: RIMM/ROMM and ProPhoto
Re: RIMM/ROMM and ProPhoto
- Subject: Re: RIMM/ROMM and ProPhoto
- From: Richard Wagner <email@hidden>
- Date: Sat, 4 Nov 2006 20:48:18 -0500
On Nov 4, 2006, at 7:03 PM, Chris Cox wrote:
The version 4 versus version 2 explains the differences you're seeing.
The ProPhoto profile was created earlier because the version 4
specification
did not exist when ROMM was renamed ProPhoto for mass consumption.
So at that time ROMM-RGB was v2 as well... so ProPhoto was certainly
not created/renamed from the current incarnation of ROMM-RGB. There
was a clear divergence of the two profiles at some point in time.
Even the profile creation software was different.
ROMM and ProPhoto are still the same, but the interpretation of the
profile versions differs slightly.
It appears to be more than just the ICC version, and "the same"
applies only in a general sense. Someone had a clear, specific
reason for the changes between the two profiles, ICC versions aside.
Actually, Adobe uses the ProPhoto V2 profile internally in ACR.
Well, Thomas Knoll has stated that ACR uses RIMM/ROMM, not a v2
ProPhoto. Why would Photoshop install ROMM-RGB for internal use (not
with the profiles generally available to users) if it was not used
internally? It is also clearly Adobe's profile. I guess the best
test would be to install a whacked-out ROMM-RGB and see what happens,
but I haven't gone that far.
ProPhoto is not outdated, it's just a V2 profile.
Fine, but it's not a V4 ROMM-RGB, either, nor does it have the
rendering intents of ROMM-RGB.
You're making a big mountain out of a rather tiny molehill here.
In addition to trying to unravel the real history behind ROMM-RGB/
ProPhoto, I'm trying to find the best way to convert ProPhoto masters
to other colorspaces like sRGB. RelCol conversions are often less
than ideal. Converting to ROMM-RGB, and then to sRGB using
Perceptual with BPC often seems to give a better conversion. Simply
changing the output in ACR from ProPhoto to sRGB is identical to
doing a RelCol conversion after-the-fact. The best way to get sRGB
conversions from ACR is to specifically optimize an image in ACR for
sRGB (this was confirmed with Thomas Knoll), but that is a lot of
work, and it will also kill the settings for ProPhoto, as ACR cannot
save multiple sets of settings. I don't see this as a tiny molehill.
Thanks for your thoughts on this, Chris.
--Rich Wagner
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