Brian Kosoff wrote:
I'm using a Jobo cpp-2 processor I am getting an uneveness in
development which jobo refers to as "road ruts" that is a linear uneveness
that runs the long length of the film, in the direction of the rotation.
It's dense on the edge, then lighter 1/3 of the way in, then denser, then
lighter then denser.
It seems to me that this is *the* inherent problem of rotary processing
and it isn't limited to Jobo machines. I'm having the same trouble with
a Mafina (
http://www.laborfoto.de/V_50gb.htm) where the film is wound
around the outside of a large diameter drum (approx. 35 cm/14") and then
rotated through a shallow pan-like recipient holding the chemicals.
While I haven't noticed any of this with rollfilm, it can be really bad
with 35 mm. Usually, it doesn't show, but on low-contrast/high density
negatives, it is quite annoying. The area along the edges is
considerably denser than the rest. Sometimes, I even get to see the
perforation pattern as density modulation in the negative.
I'm attributing this mainly to turbulence caused by the perforation.
Hand agitation obviously isn't a viable alternative with C-41, let alone
E-6. Any other suggestions?
Ralf
--
Ralf R. Radermacher - DL9KCG - Köln/Cologne, Germany
private homepage:
http://www.fotoralf.de
manual cameras and photo galleries - updated Apr. 11, 2003
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