If it can't be a film problem or processor problem then it has to be a camera problem. Since you are not getting it with the Rollei I'd guess you might want to check your first shutter curtain and your second (follower) shutter curtain. Shine a bright light(those little multi-bulb LED flashlights work great for this) in the front of the camera with the lens off, mirror lifted up if possible, and look from the backside at the curtain. Do this in a near dark room. Could be an insect riddled shutter curtain. Don't laugh! I've seen curtain cloth damaged by little odd grubs that like chewing on that type of material for some odd reason. JohnW