... Also, I have heard good things about Museo Portfolio Rag, except that it fares poorly in longevity tests. Can anyone confirm this?
Here are some lightfade test results for a couple of different printers:
ipf5000/Canon Lucia ink/Portfolio Rag Aai&A Conservation Display rating = 60-94 Megalux hours
ipf5000/Canon Lucia ink/Hahnemuhle Photo Rag Aai&A Conservation Display rating = 116-156 Megalux hours
Epson 7800/Epson K3 ink/Portfolio Rag Aai&A Conservation Display rating = 28-56 Megalux hours
Epson 7800/Epson K3 ink/Hahnemuhle Photo Rag Aai&A Conservation Display rating = 64-84 Megalux hours
Note: divide megalux hour ratings by two if you want "years on display" predictions according to industry standard extrapolation of 450 lux illumination for 12 hours per day.
So, about half the light fade resistance for the Lucia ink set comparing portfolio rag to HN photo rag, similar fade factor ratio for K3 ink set, but lower overall mainly because K3 is less fade resistant than Lucia. Yet K3 with HN photo rag brings the Epson 7800 on par with the iPF5000 printing on Portfolio Rag. Media makes an important contribution! It's not just inks.
Both Lucia inks and portfolio rag have undergone some reformulations since these tests were done, so more new tests would be worthwhile, but the ink receptor coating of the Portfolio Rag is claimed by the manufacturer to be the same (only known change was said to be in the supplier of the base paper). Hence, I'd think these results will still be reasaonably valid.