Hello, I have here 3 sheetes of pola 55 PN 4x5 - had 10 - expired march 2001 after 7 tries and getting no image i thought, "of course they are expired!" but then i thought, "maybe they are not getting exposed, when i pull the envelope to expose the whole thing is coming up the holder." so, could it be the film holder has a problem? is it really the films? help! not gonna do anything for now. Thank you !!!