"Luis Ortega" wrote in message
...
Thanks to all. I need to check out the various suggestion
offered. To clarify, the defect is not an undevelopment
effect caused by the rails of the reels impeding the
developer along the sprocket hole areas but something
that is happening only inside the negative frame itself.
It is very evident on a contact sheet when you can see all
of the frames side by side. Each contact frame appears a
little whiter and more washed out along one edge, usually
the bottom edge but sometimes the side edge.
I work in a school and see dozens of cameras in the
darkroom so I can't do a lot more than try to follow it up
as it happens, but I am curious as to why this is
happening.
Thanks to all.

If the effect is inside the frame its obviously happening
in the camera. Since it seems to happen on different edges
in various pictures its not likely the shutter. It _might_
be an internal reflection of some sort. The way to find out
is to put a small piece of ground glass in the film gate,
open the shutter (T exposure) and shine a flashlight intot
the lens from different angles. Actually you may be able to
see a reflection just by eye. The cure is to paint whatever
is causing the reflection with flat black paint or some
other light absorptive material.
It is possible for a focal plane shutter to cause a band
of under or overexposure at one end of its travel but it
will consistently at the same place on each frame. It is
also possible for a focal plane shutter to cause spots or
steaks on frames if it has holes in it, but this sounds like
something that is not shutter related.
If the camera is an SLR check for light leaks from the
finder when the mirror is in the up position. Sometimes the
light seals in SLR's get old and don't work. Unless you eye
is pressed right against the finder some light can get in
and cause some form of fogging. I am suggesting this only
because your problem seems to be a little unusual and the
cause may be a bit unusual.


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Richard Knoppow
Los Angeles, CA, USA