Archived posting to the Leica Users Group, 1999/01/21
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 06:34 PM 1/20/1999 -0700, COLBYG@ULV.EDU, you wrote... > My test with Tri-X revealed no obvious scratches, from either body, but >I haven't yet tried to scan the negatives. In my experience, a CCD film scanner will reveal scratches so minute they don't even show up when you print the negatives! > Does anyone know if there are any "usual suspects" within the body? The >pressure plate comes immediately to mind. Someone wrote that small dust >particles can make the scratches. I'm especially concerned about the force >required on the rewind crank; it's much more than that required on the Nikons. > Unfortunately my M4 has film in it so I can't go look at specific areas. The pressure plate, of course, is suspect. Any other roller, etc. which would contact the base side of the film as it advances is suspect. If the problem is regularly on every roll, not just some random scratches on some rolls, then it is likely to be a particle stuck to something or some nick, burr, or scratch--not random dust particles floating around. Run a finger along the leading and trailing edges of the pressure plate; you might feel some scratches or nicks that you can't see. Sometimes you just can't see or feel anything obvious. I once went through a similar problem with a Canon F-1 of mine. After cleaning the pressure plate, etc. thoroughly with film cleaner, alcohol and everything else I considered safe, the problem was _still_ there. Finally, I used a very fine abrasive (cerium oxide) on a roller which helps keep the film snug against the sprocket drive and that solved the problem. But I never actually saw the offending particles. - -Mike