> >...
>
> Has anyone compared the results of tube processing with those of Jobo
> processing. I have never managed to master my Jobo CPP-2 to "perfect,
> even development". So, I am back to manual, tank processing. I am ready
> for more tests though!
> Pierre Chiha
>
According to Fred Newman at Darkroom Innovations, the company that sells
the Phil Davis designed BTZS tubes, the tubes should give you results
that are very similar to the ones that you'd get with your Jobo CPP-2
processor and Jobo expert drums. Since the expert drums give the film
constant agitation, then you must constantly agitate the tubes to get
similar results.
I started out using the Phil Davis "Behond the Zone System" (BTZS)
designed tubes, but have since purchased a used Jobo CPP-2 and expert
drum. I am happy with the results of both systems and have found that I
don't have to redo my film calibrations when moving from one system to
the other.
Are you using the Jobo expert drums or the 2500 series drum with the cut
sheet film holder? If you are using the 2500 series drum, then I would
expect some differences in results between the two systems. I log roll
the tubes, as recommended, and reverse the direction of rotation very 30
seconds.
I recently lent my set of tubes to someone new to 4x5 so that they could
try them out. I still use them for film calibration because I can
develop each sheet of film for a separate time in one run (following the
Davis instructions). Using the Jobo, I'd have to make five runs.
There are a few things that you can do to make sure that you get
consistent results with either the tubes or the Jobo
1. Always use the same amount of developer for each run. The BTZS
tubes use 2 oz. of developer per sheet of film. When using a Jobo
3006 expert drum that can develop 6 sheets of film, I use 12 oz.
of developer.
2. Always give the developer about the same amount of work to do.
If you are using a Jobo expert drum to develop less than the
maximum number of sheets that the drum can hold, put in one
sheet of fully exposed film for every two sheets missing. This
doesn't need to be the same film that are using. It can be older
outdated film or cheaper lith film.
3. When using the Jobo, make sure that you measure the temperature
of the developer before you start to make sure that it has come
up to the temperature of the waterbath. If you rush things and
try to start developing as soon as the waterbath says that it is
at the correct temperature, the developer may still be a few
degrees cooler.
Overall, I've been very happy with both the BTZS tubes and the Jobo
processor with expert drums. I also use the Jobo for all of my rollfilm
developing and find it very handy for doing my own E-6 developing.
Using the tubes for E-6 would not be very practical.
Several Jobo representatives are very active in the rec.photo.darkroom
newsgroup. If you have questions about using their equipment, I'm sure
that you'll get good advice from them. If you don't have access to
NEWS, then you may want to call Jobo.
Good luck,
Bill Patterson