I store a 7x17 negative in half a sheet of 16x20 archival paper, cut to 16x17.5 inches and folded to 8x17.5. Since I bracket, the lesser shot is stored in-between. Stacks of them are stored on the 7 inch edge in an archival box. HollingerMetalEdge.com makes all sorts of archival box sizes. They even made up some for the ulf crowd that have sold well. Remind me when you are here next month and I will show and tell.