Here's my $0.02 on the subject of developing tubes. I have used 3
methods of tube development for sheet film: Jobo, BTZS, and Beseler
color print drum on motor base. Each has its +s and -s.
The Jobo, which belongs to our artist in residence here at work,
handles up to 5 8x10s at a time. It produces perfectly even
development and is chemically efficient but each negative in a load must
necessarily receive the same development time. If the rotation speed
can't be made slow enough for the contrast you desire, it is possible
to modify the motor speed (I don't remember the details of how).
Which raises the question, why not adjust your developer dilution to
produce the desired contrast?
The Beseler drum, an admittedly primitive system, is what we use here
for developing 4x5 and 8x10 copy negatives. I also use this system at
home. The drums can be found in a wide range of sizes, but avoid
those with especially large "fins" on the inside. Also don't lose the
inserts for smaller film sizes. The 8x10 drum holds 1 8x10, 2 5x7s,
or 4 4x5s. I use 2 oz of developer per 4x5 - 8 oz for a full load.
At a recent workshop I got to try the BTZS tubes for 4x5. I was able
after a little practice to comfortably handle 6 4x5 tubes at a time.
The only drawback to this system that I can see is that the tubes are
rolled manually which means that you can't be doing something else
during those long development times required for contrasty
alt-process negatives. An interesting note here is that the only part
of using these tubes that must be done in total darkness is loading
the film and then switching from dry caps to the second set which
contains the developer. It is not necessary to presoak. Different
development times, different developer dilutions, different
developers, even different films can be processed at once since each
tube can be removed at its designated time. Under safelight or dim
incandescent light the cap is removed and the open tube is put into a
tray of stop bath and spun. Film is then removed and placed in tray
of fixer, etc.... I was rather skeptical about this procedure at
first but at the workshop Phil Davis demonstrated conclusively that
it works - there is no fogging and development is perfectly even. I
recently got a set of 4 8x10 tubes which I tried for the first time
last night. I found that keeping 4 tubes of that size spinning at a
fairly constant rate was rather difficult. Some sort of automated
rotation system would make this method ideal in my opinion.
Keith