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So, where can I learn about EEM paper?
EEM (Epson Enhanced Matte), unless something has changed, is cheap, acidic paper. That's all you really need to know about it.
I think you must have meant some other type of paper. The Epson Premier Art Scrapbook paper that I mentioned is the same as your Premier Art 205. I assume they'll disappear at the same time if/when that happens. For better or worse, dmax wins over other, sometimes conflicting goals in paper design & sales.
The other papers I mentioned are the Epson Hot Press natural, the likely successor to the Premier Art 325 I've used for years, and Arches Hot Press, which may be the most famous and best watercolor (uncoated) paper. I use Arches Hot Press Bright White (not really "bright" at all and no OBA's) full sheets (22 x 30") to make what I consider the most archival, collectible prints of that size. (I don't trust coatings. See, for example http://www.dp3project.org/preservation#crackinginkjetlight and http://www.luminous-landscape.com/forum/index.php?topic=87926.0 .)
Paul