Alan:
Thanks for the tip, can you list some brand examples? Newspaper is acidic for sure.
Mike, the post on Epson EFP, is a good point. It's also one of the only papers I have found in large sheets and every once and a while Atlex will have them on sale. Someone already mentioned Canon Platine, I love it 100% cotton with a similar finish to Epson EFP. Platine won't out gas to the front and has a nice semi-gloss finish. You can also consider Canon's Baryta photographique paper, however it's alpha cellulose not 100% cotton. I feel it has a more pure glossy finish, and it is very easy to scratch, either in the printer or when mounting.
Also, Breathing Color's Vibrance Rag, a newer paper. It's also 100% cotton, but has a more aggressive finish.
Of course this is off topic as you are using RC paper. All of them will out gas to some extent. I have pulled back and remounted enough prints that for commercial work I no longer quote it, and use a fiber based paper.
Paul Caldwell