I too would second those words of advice, but would add that the little stainless steel balls in the Paterson reels must be completely free before you start loading the film. Just try moving them about with a fingernail or ball point before comitting the spirals to the changing bag. For some reason the balls are prone to get stuck, especially if the reels are well worn. (One of mine dropped out altogether). By the time you have unrolled the film, and found that you cannot load it onto the spiral it may well be impossible to resolve the problem without letting light into the bag.