I was recently given a box of 4x5 holders, and in the box was a curious roll film holder. I'm looking for any information about it (like what camera it was used with, film that might still be available or possible to reroll and adapt.) The holder is the size of a 4x5 holder, and about 2 or 3 times thicker. The back has a very deep peephole, (ostensibly to read the paper back numbers?) Inside the holder, this is what it says: 5x4 Graflex roll holder 1915 Use # 53 Eastman Graflex film, Eastman Kodak. I can't find any info about #53 film, but it looks like 4x5-sized roll film. The back still has empty wooden spools inside.