[piffey]

Doesn't always work. I've got old Agfa negatives I developed from my grandpa in Korea in the 50s. Developed them after finding them in his attic maybe 10 years ago now. They sat between two panes of glass for 5 years with volumes of books on top, not a single change toward flat. I finally gave up and just put them in the archival sleeves and in the binder with the curve.