Hi! I use an old Polaroid back for sheet film (4x5) with my pinhole camera. I have a problem when I want to get the film out of the holder as the metal strip on the film envelope seems to get stuck somewhere and I have to pull very hard to get the film out. That does not help even development and I'm always missing a corner of my picture. From the figures in the Polaroid manual, I kind of guessed that the metal strip should be able to get out of the holder together with the film. I opened the holder and even with everything at the right place (there are not so many parts), the film does not get out smoothly. Did someone here also experienced this problem? Any tips to solve it?