For some of the 8x10 stuff I don't frame I put them in  a sheet protector like to put notebook paper in. I put a piece of black construction(acid free for all you picky folks) then I put it in a notebook. Folks that stop at my booth seem to like to look through the notebook.  I finish  my portraits on both sides and edges with clear spray. Usually the Wal Mart brand for .99 a can. I haven't noticed moisture being a problem. Now I ain't no genious to figure this one out. I read about on one of these scrollsaw sites. Yee Haw!  gw