ProPhoto and ROMM
ProPhoto and ROMM
- Subject: ProPhoto and ROMM
- From: email@hidden
- Date: Fri, 25 Aug 2006 14:29:17 -0400
First, the name...
Kodak renamed the ROMM RGB to ProPhoto RGB a few years ago in order to promote adoption in the Pro Photographer arena.
We had found that the ROMM primaries were good for rendering from unrendered data (like Raw for digital cameras, or Reference Print Density for negatives).
Bruce Fraser pitched in with some help, in particular, documenting a 'profile-assisted' method instead of a 'profile-driven' method.
The profile assisted method is:
- Scan an image at a low contrast
- convert from a linear custom input profile to ProPhoto RGB
- add tonal contrast with curves in 16 bit
He wrote this up in the article at: http://www.creativepro.com:80/story/feature/8582.html
Second, the difference...
Klaus Karcher's post of August 24 got it right:
"I recognized that ROMM-RGB has completely different Whitepoint:
X: 0.8581
Y: 0.8900
Z: 0.7342
This may conform to the spec "The reference medium is defined as a
hypothetical print on a substrate specified to have a neutral
reflectance of 89%" (http://www.color.org/ICCSpecRevision_22_02_05_PRMG.pdf)"
When Absolute Colorimetric gained favor a couple of years ago, we found that RC and AC produced the same results.
Therefore, we changed the media white point tag according to the ICC spec, which delivers a darker white point when AC is invoked, which sets up better soft proofing of the media white of a given output profile. The ProPhoto working space delivered by Adobe is the older version, before the change.
We will make the updated profile available to our licensees (including Adobe) for delivery in future releases.
I will also try to restore the posting of ProPhoto RGB to Kodak.com for end user download.
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