P3D SEVERE vertical variation (Colorist)

[Paul Talbot <ptww@xxxxxxxxx>]

I was recently tutoring someone on mounting concepts.  She
was fairly new to doing her own mounting.  Though she had
been using heat seal mounts for some time, she didn't yet
understand the stereo window, window violations, vertical
or rotational errors, etc.  She had started to mount with
Spicer mounts but was complaining of problems she was
having.  She showed me a slide that she said was causing
her particular difficulty.  I looked at it in a Red Button
viewer, and at fist it seemed fine.  Well that shows how
"floppy" my eyes have apparently become.  When I looked one
eye at a time to compare the left and right images, I
spotted the enormous vertical misalignment.  "Aha, I need
to show her how to be sure the chips are aligned vertically."

Well...good luck!  The two chips, from a TDC Colorist, had
so much vertical disparity that it was beyond the range
of the mounting jig (cut up RBT mount)--and even beyond the
range of an uncut RBT mount).  "Aha, I need to show her how
to use a mounting guide instead of a mounting jig."

Well...good luck!  The two chips had so much vertical
disparity that when they were in proper alignment
vertically, the common image area wasn't even tall
enough to fill the aperture of a normal mount!  "Aha,
I need to show her the nifty Spicer 5P landscape (aka
"reduced height") mount!

Success at last!  :-)

Examination of other chips from the same roll of film showed
SEVERE variation of vertical alignment--some shots on the SAME
roll had fairly accurate vertical alignment.  I could not believe
my eyes!  I thought it was a big hassle when the chips from my
Realist vary by .05 to .1mm in vertical alignment, but this
much variation was really astonishing!

(Further study of the film showed that the mounting problems
were made worse by the fact that the camera did not expose
the full vertical amount of film between the sprocket holes.
(Though sometimes the image of one chip did go into the
sprocket holes, while it fell *far* away from the sprocket
holes at the other side of the film.)

The images on another roll, shot with her Realist, extended
slightly into the sprocket hole area, giving much more vertical
room with which to work!

Has anyone else ever seen this level of variation in vertical
alignment within one roll of film shot in a stereo camera?  If
so, how do you do your mounting without going crazy???  Can the
camera be repaired to a better working condition?  

What about the small vertical image area?  Is that normal for
a Colorist?

Paul Talbot