Check out Red River Paper, they offer a complete selection, almost all of which are available in 17x25. Their Arctic Polar Luster or Ultra Pro Satins are probably what you want, depending on the amount of texture that you prefer. I suggest that you try their sample pack and also download the paper profiles for your 3880.
I second Mick's Red River recommendation. I've made several prints on their Artic Polar Luster 17x25 with my 3880.
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well, if I may : nobody cares about the US standard paper size and the history of documents printing... Many people today want something that can fit easily the 3:2 ratio and 17x25 is perfect for that. I am using the 3880 and am not interested to cut manually sheets from rolls. I much appreciate the sheets already available in 17x25. Hahnemuehle (the wonderful Harman Gloss Baryta), Redriver and some others finally got it... Hope Epson will wake up somedays and realizes it can make money from 2015 context.
Was going to suggest looking into the Hahnemuhle line of papers as others have. You can get what they call a Media Sampler from them, which is a corner bound 2 X 4.5" of approx 40 different archival papers samples they offer for giclee/jet printers. You can then always have it handy as reference. If you can't get it directly then you might be able to get it through one of their authorized print providers (their site has a listing so you might find a source there.
Yes, choosing cut sheet sizes can be a little frustrating for those of us who shoot 35 mm format and like to print our own prints. But, to be fair, there a lot of other formats out there, and there are many (mostly commercial/professional) out there printing for other reasons than for photographs. This is primarily why Epson (and most other printer manufacturers/paper manufacturers) stick to known standards, not established by a particular camera format, but by what is considered traditional in the print industry/commercial photography. I agree that this is somewhat arcane at this point (with the millions of 35 mm owners out there) from the photographer's perspective, but in reality the bigger market (and a market that tends to replace printers more often, read: repeat business) is still use the old standards. Change is slow to come when a huge industry is set in their ways.
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