For what it's worth and without wanting to re-stoke the Epson paper conversation, Epson Exhibition Fiber paper is not doing very well in Aardenburg Imaging's testing. Paper white is degrading and not all of it can be explained by degradation of its high level of OBAs. Below are a couple of quotes from Mark at AaI&A. I just use this as an another example (in addition to QTR Create ICC) of being able to improve on Epson's offerings in a number of ways.
"Perhaps more importantly, the initial UVincluded-UVexcluded delta b* measurement was 6.5 for this sample (see the "UV delta b* Influence" category in the AaI&A database for these media whitepoint measurements). That value puts this sample in the high OBA category, but it also means that only delta b*= 6.5 out of the delta b*=10 at 140Mluxhr can be explained by OBA burnout. The fact that the delta E shift for the media white point has surpassed 6.5 (and as Ernst noted is now greater than delta E=10) means either that the OBA degradation products are not totally colorless, or there are other chemistries starting to discolor, or both. Exhibition Fiber paper has the dubious distinction to be the first paper in the AaI&A database that displays this phenomenon.
Paper choice is a very subjective thing for most printmakers. There are numerous desired initial appearance properties to consider, and comprehensive information on print permanence is often hard to come by. That said, these surprising lightfastness test results for EEF should give digital FineArt printmakers some pause to reflect.
"Ernst mentioned Hahnemulhe Fine Art Baryta, not to be confused with Hahnemuhle Photo Rag Baryta. Hahnemuhle reserves the term "rag" for cotton base paper. and rag is absent in the HN's naming convention for its alphacellulose base papers. So, Fine Art baryta is alphacellulose base and it also has considerable OBA. Ph Rag Baryta is cotton base and has no OBA. The HPR baryta with no OBA outperforms the HFA baryta in my testing. HPR baryta is an excellent choice for lightfastness and compatibility with the major OEM ink sets, HFA baryta not so much.