Re: vertical frame spoilage

["Elton N. Kaufmann - Cycloid Fathom Group" <cycloid@xxxxxxxxxxxxxxxxxx>]

Seems clear to me that regardless of your precautions, you had a light
strike on the light trap of the film canister.  The strike extends to the
film edge (into the sprockets) so the light did not come from anywhere on
the shutter side of the film in camera.  The pattern from frame to frame is
consistent with the light slicing into a coiled roll in canister.  The
spacing won't be equal because the number of frames per circuit on the
spool changes with radius and  the light can also bounce around a bit
without the antihalation layer to stop it.  This happened to me once and I
never was sure why.  I assume I absent-mindedly let the canister see the
light of day somehow.  Why not just try to shoot a roll (of unimportant
subjects) as a test of your equipment and procedure.
							Good luck,
								EltonK

>Date: Sun, 26 Apr 1998 00:16:32 -0400
>From: siteseer <siteseer@xxxxxxxxxxxxxx>
>Subject: vertical frame spoilage
>
>        I'm having a problem with vertical streaks appearing in many frames
>of the Kodak HIE film that I shoot.  I have a .jpg of the contact sheet at
>
>http://www.jorsm.com/~siteseer/contact.jpg
>
>so you can see exactly what I am talking about.  The streaks appear to have
>the same jagged silhouette pattern, but appear in different places in the
>frame, like 1/3 from right, 1/5 from right, and near the right edge.
>
>        I was wondering if anyone else saw the same results in their
>shooting, and if so, what they did to correct the problem.
>
>        I use a Nikon N2000, manual focus only, have black electrical tape
>on the small window on the back of the camera that shows what kind of film
>is loaded, so no light is leaking there, plus tape around the edges of the
>back.  I loaded and unloaded the film in a totally dark room in a Rokunar
>changing bag, and only took the film out of the plastic can while in the
>bag.  The film was kept frozen until shot, and the shooting time was around
>1 1/2 hours, with additional travel time of 2 hours before the film was
>refrozen.  My shutter is a vertical shutter (the leaf goes up and down),
>meaning if the problem was a shutter hang-up, the streak should be
>horizontal instead of vertical.  The edge of the can should not be a
>problem, since it never sees light due to the way I keep the film in total
>darkness when loading and unloading.  I was thinking it might be a lens
>diffraction, but the streak looks the same in the vertical pictures as in
>the horizontal ones.
>
>        All shots were at 1/125, bracketed at f8, f11, f16, except the one
>series of four, which started at f5.6.
>
>        I hope that's enough information to go on.

Exhibiting fine-art and editorial photography
Cycloid Fathom Gallery
Elton N. Kaufmann, Chairman
P. O. Box 8129
Downers Grove, Illinois 60517-8129
USA
cycloid@xxxxxxxxxxxxxxxxxx
http://www.cycloid-fathom.com/gallery/
ftp.cycloid-fathom.com/group/uploads/

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End of Infrared-Digest V0 #531
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