I've done a swag more testing with the Moab Somerset Museum Rag (MSMR) this evening and I am a complete convert for this paper. So much so, I have gone back and re-printed a dozen images that I had thought I had finished on Hahnemuhle PhotoRag Baryta for comparison. I far prefer them on the MSMR. The Dmax is better on the HPRB (but not by much for a gloss v. matt comparison); but in every other area, colour depth, feel, tooth, texture, I prefer the MSMR. In the hand its gloriously supple and velvety. I gave two prints to my wife - one on HPRB and one on the MSMR. Her immediate reaction as a non photographer was 'I prefer the semi-gloss'; being taken in by the gloss as most non photographers are. But within seconds she changed her mind saying she preferred the depth of colour, feel and look of the MSMR. There is something about this paper that just really appeals.
Compared to my traditional favourite HPR and Museum Etching the MSMR is better on all counts (especially dmax and colour depth) - although the heavy tooth on Museum Etching is something I still like for certain images. I cant see myself printing on HPR again now I have this new MSMR paper.
I managed to get a 17" roll and a box of the 13 x 19 MSMR locally (cleaned them out of stock). I notice however Moab do not as yet produce this paper in A3 and rolls larger than 17" are limited in size (some sizes not yet available). Hopefully its not far off as I will be doing a lot of printing on this new Rag paper in the future.
One thing to be careful of - this paper does require a good brushing before putting through the printer. I ruined my first A3+ sheet because some small fibres came off after it had been through the printer leaving white spots on the print. A good brushing solves the problem removing any loose fibres.
Prints definitely benefit from some subtle soft proofing tweaks (such as a curve tweak, and a little +5/+8 Sat. boost) in PS to compensate for the matt paper - so it is more work than something like HPRB; which you can pretty much print straight from a processed file without softproof tweaks. But its worth the effort and a gorgeous paper.