I just got my second roll back shot with my Bronica SQ-A. The first roll was completely free of light leaks, but the second one was full of them. For the first roll I shoot entirely on a tripod, and advanced to the next frame before reinserting the dark slide. For the second roll, I shot entirely handheld (except for 1 tripod shot). Because I was fumbling with the camera, I inserted the dark slide before advancing the crank with each shot, and the one tripod shot where I wound the film before inserting the slide is the one shot on the roll without a light leak. Could my sloppy darkslide handling have caused the leak? Is there a way to test for leaks without burning through film? Also, is there any reason to use a dark slide if I'm not changing out backs? I also noticed black splotches on some of the frames. Does anyone know what this could possibly be?