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 17:21:11 -0500
On Nov 4, 2006, Chris Cox wrote:
I've had trouble tracking down the significance of the differences
between ROMM RGB and ProPhoto RGB.
I don't know which specific profiles you're looking at - but
ProPhoto really
is ROMM with a more user friendly name. And ROMM is normally just a
matrix/TRC profile (that was part of their design goals), so I
don't know
how it could have all 3 rendering intents.
Chris
Chris,
In Photoshop, make a new document, using ROMM-RGB as the profile.
Save it, embedding the profile. Extract the profile with the utility
of your choice. It is not the same as a ProPhoto profile extracted
in the same manner, as output from ACR - and it is not just the name
that's different. Some of this (e.g., the media white point and
black point differences) was confirmed earlier on this List. Plot
them both (esp. in Luv or Yxy) and these differences are apparent.
The ROMM-RGB profile is " C o p y r i g h t 2 0 0 2 A d o b e
S y s t e m s I n c o r p o r a t e d"
The ProPhoto profile is Copyright (c) Eastman Kodak Company, 1999,
all rights reserved. desc
ROMM-RGB has a device type of "Print," whereas ProPhoto has a device
type of "Monitor."
ROMM-RGB has a creation date of 2002/10/15, compared to 1998/12/1 in
ProPhoto.
ROMM-RGB is an ICC Version 4.0.0 profile.
ProPhoto is an ICC Version 2.1.0 profile.
There are A2B0, A2B1, A2B2, B2A0, B2A1, and B2A2 tags corresponding
to RGB->XYZ LUTs for Perceptual, Colorimetric, and Saturation in ROMM-
RGB. This is very much unlike ProPhoto, which has r, g, b TRC's and
XYZ colorant values. The curves for AbsCol, RelCol, and Perceptual
are different from each other in ROMM-RGB, unlike ProPhoto.
If ProPhoto simply has a "more user friendly" name, why all the
differences? And why the creation date years before ROMM-RGB? And why
different ICC versions? And why does Adobe bother to install ROMM-RGB
internally with Photoshop?
As Adobe apparently uses ROMM-RGB internally in Photoshop/ACR (that's
where the profile is installed), I'm wondering why Adobe chose to use
the seemingly outdated ProPhoto profile as output from ACR, rather
than what appears to be a more modern, and more useful, and more
appropriate ROMM-RGB. Surely photographers and others could adapt to
a name change...
Thanks,
-Rich Wagner _______________________________________________
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