[Leica] Problem with M6 scratching film

["Mark E Davison" <Mark_E_Davison@email.msn.com>]

I'm a Leica newbie and had a recent experience I thought I would share with
the LUG.

In trying to buy a new M6 body I ran into a batch of bodies which left two
trails of scratch marks on the back of the film (the shiny side away from
the lens). The scratch trails look as if someone had run two small abrasive
pads down the length of the film, just inside of the film rails. On
developed film you cannot see the scratches with a loupe, but they show up
on scanned slides (Nikon LS2000, with and without ICE automatic defect
correction turned on,) and you can see the scratches with the naked eye if
you hold up the film so you can see the reflection of a light source (like a
small flashlight).

I sacrificed a roll of unexposed film (Kodak royal gold 400) and determined
the following:

1. the scratching occurs when the film is transported in the M6. The same
film goes through my OM4Ti with no scratches, so I don't think it is the
film cassette.

2. the film pressure plates on all 3 offending bodies were VERY abrasive: if
you lightly brushed the back of a piece of film across the plates, visible
abrasion occurred on the film. No such abrasion occurs on my OM4Ti, or on a
random M4 chosen for testing.

The three bodies that scratched had serial numbers of the form 2433xxx.

Glazer's Camera in Seattle was very understanding with me, and kept swapping
bodies until we found one that didn't scratch. We finally settled on a body
with a serial number far away from 2433xxx.

Surprisingly, every modern classic new M6 that we looked at has a somewhat
abrasive film pressure plate, as shown by the film back scratch test, but
not all of them leave scratches on the film in actual use.