From a recent FAQ in the XRite download section:
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PM5 Optical Brightener Correction -> How to achieve in i1Profiler?
Question: ProfileMaker 5 did include a software-based option for Optical Brightener Correction (OBC) at least for the Perceptual table in a profile. If the software detected optical brightener in the measurement data, a checkbox for OBC was enabled and could be switched on or off. This helped me to avoid color casts in a profile. How can I achieve this with i1Profiler?
Answer: The new i1Profiler software includes a completely new profiling engine, which provides already by default a most neutral gray axis and this effects on all Rendering Intent tables. This has also been confirmed for papers containing optical brighteners.
Additionally, i1Profiler provides a special option to enlarge the range of how far the neutralisation of grays goes into the more chromatic color areas: Profile Settings -> Perceptual -> Neutralize Gray. This allows to increase the neutrality of the gray axis further.
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And I agree with their statement as far as it goes, i.e. a non-uvcut profile seems to render an image to the printer identically as compared to a uvcut based profile. However, I typically invoke soft proofing on my images and then perform final edits for printing, therefore it's important to me that the back path rendering be as accurate as possible. And I don't believe they included Absolute in their group of rendering intents.
Red River Ultra Pro Satin measures about -3 on the b axis, Epson Premium Glossy about -4. Both of these values go close to zero when the paper is measured with an uvcut instrument, resulting in a very different white point, and therefore a different Absolute rendering (for those who may not be aware the Absolute rendering intent is calculated from the Relative intent, using the white point to appropriately bend the curves). I certainly agree the dual measurement and subsequent calculation using an Isis is the best solution, however there are still a lot of us slogging along with i1Pros, and I believe the uvcut version provides the best softproofing on papers with significant OBAs.
Richard Southworth
Added by edit - Alan, my statements were only in regard to i1Profiler, I agree that OBA compensation, such as I have with ProfileMaker, can do a reasonable job with an i1Pro-normal.