I've done both cellar and upstairs, and upstairs is better. In the cellar I once had a former coal bin entirely wrapped on the inside with foil-faced kraft construction paper -- it was like printing inside a cookie box, very bright, reasonably clean, but humidity was a nightmare, and ventilation was limited. Now I'm in a spare bedroom on the first floor where I've plumbed in a sink, covered the window with a World-War II blackout shade and sealed the door satisfactorily with the black plastic paper is wrapped in. A low-velocity exhaust fan runs continuously when the room is in use; odor has not been a problem. And I have floral wallpaper. -bill h