You know those daylight loading holders for bulk 35mm film?
I want to make something similar for 30" roll paper. That way I can just pull paper off the roll as I need it. Right now the roll lives in a cardboard box in a black plastic bag. It's hard to get it out, and cut off enough to use, and put it all back. On the other hand, if I could just pull out however much I need and slit it off with one of those box cutter things, it would be very convenient.
I'm thinking a plywood box, with some kind of felt light trap like a giant 35mm cassette. I would be most of the way there, though, if I had a trap door that I had to close before turning on the white light.