Hello everybody,
I'm a usual visitor of this forum, although I don't contribute that much.
Now, I have a problem with some exposures that I would like to share,
in search of a solution.
As you can see in this image
the top part is veiled with an additional exposure. This is a scan of a 9x12
HP5+ negative, but I have other examples with 4x5 Trix (which, by the way,
I think that rules out a defective back). I have other examples showing the
same problem: a large part of the top of the image fogged. All the pictures
were taken with a Linhoff Master Technika and a 150mm apo symmar, around f22
and with an important front rise. Other pictures taken the same days with
the same hardware came out fine. The negatives were developed in a Combiplan
tank, and in the same batch there were correctly developed pictures, which rules
out development problems (I think).
Up to now I'm guessing that the problem is the following: the 150 apo symmar
is mounted in a recessed board whose back is slightly shinny. This is more visible
with a front rise. Under certain conditions, the light bounces back from the
surface of the negative onto the board and, then, back again on the negative.
The front rise sends the light to the bottom of the negative, which is the fogged
part.
Anyway, has someone seen a similar problem before? Am I right with my guess
or should I consider something different?
Best,
Pau
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