I need a way to stow 5x7 and 8x10 sheet film that has been exposed. I'd like to unload it from film holders in a changing bag and then reload film. Obviously I'd like something that is opaque and sturdy but won't scratch the emulsion. I thought of making something out of delrin and lining it with fiber paper or something like that. Perhaps there is a product already on the market that some of you use? Any ideas?