[Leica] Light leaks on Leica IIIc (380xxx)

[Matej Novak <matej.novak@hermes.si>]

ello,

 I just got a 1941 Leica IIIC (380xxx) with non-standard flash
sync installed. When I have had developped the first roll of
film I noticed that there are bright stripes of irregular shape
on some of the slides. The stripes extend from the holes on the
lower side of the film up and through the holes on the upper side
of the film (if you think about the film in the camera it is
vice-versa). Most of the stripes are on the right side of the
slides, except one that is on the left side of the slide (all
are of the similar shape).

 I was giving it a lot of thought, and I have narrowed the possible
cause to one of the two:
1. The second curtain is too loose. It seems to me that the second
   curtain is a bit loose. When thinking about the light leak on
   some of the slides and its absence on others, I could attribute
   it to the fact that sometimes I did wind the film right after
   shooting, and sometimes not. I have compared the tension of the
   second curtain after firing the shutter on my IIIc with my IIf,
   and the IIIc was perhaps a little bit more loose but not
   significantly. When start to wind the film the second curtain
   gets tight as I would expect it to be.

   If this is the case, please advise how to increase the tension.
   I have tried adjusting the second curtain tension adjuster, but
   the curtain was still loose.

2. There was some kind of problem with the film. Either the lab who
   developped it, somehow exposed it to light, or the film container
   itself somehow leaked light. I'll try the second roll and have it
   developped at another lab, to verify this hypothesis.

   Any opinions or suggestions?

Thanks in advance,
Matej