I've just developed a B&W film shot with my Pentax MX. In some of the frames the right hand edge is streaking into the negative ... and the gap between this and the next frame is wider than normal. it's not on all of them, just a few in the middle and so I'm not making the same mistake/ camera fault (?) all the time. I reckon I am just not winding on fully. But if so, why is the right hand margin streaked rather than a neat space but wider? Needless to say, I've done in the best frames.