The expert drums are a largish black drum with 10 individual chambers that you
load the film into. Each chamber is similar in size to a soda pop can.
It looks a lot like the chambers for the Colt 45 revolver except that you load
films instead of bullets. You can load up to 10 sheets into the drum.
There is a version for 4x5 and a larger version for 8x10 films. These Jobo
drums are rather
expensive: more than $200 US if my memory serves me correctly.
My Jobo is set to 50 rpm and since I have had excellent results from the
beginning, I have never changed from that setting. The developing action
is wonderfully even and consistent for my requirements: landscape, tabletop
and figure subjects. (The negatives are developed for printing onto
standard silver-gelatine paper a condenser light source).
However, the Jobo system will not work for extreme contraction like
an N-3 development because the agitation is too agressive. Photographer John
Sexton has developed a "slosher" tray development gizmo for those occasions.
I plan to try that when the need arises. Naturally I would be interested if
anyone
has been able to get good N-3 development using the Jobo equipment.
Here are the details of my processing:
Type of film: Tmax 400, and Ilford FP4 Plus in 4x5, and Tmax 100 and 400 in
120 size.
Chemistry: Kodak Tmax developer, Ilfofix, Kodak Hypoclearing Agent.
Time, temperature and solution dilution are done according to the
instructions on the
packaging. I adjust the time in the developer according to my exposure
requirements
but a lot of film goes through for 7 minutes at 24 celsius. Jobo users have
been told to use the Tmax-R developer with the Jobo drums to avoid a possible
dichroic fog problem with Tmax films. But I have never had a problem with this
in my setup and I use the ordinary, cheaper, and easy to find Tmax developer.
By the way, my wife ran a custom lab for many years and ran *all* the black
and
white film development with the Jobo and Tmax developer combo with
excellent overall
results.
Using the hypoclear according to the package instructions gets rid of the
"pink"
T-max stain that many people complain about. I think that using one-shot
solutions also helps.
Tmax is a film that is very sensitive to process variations, and needs to be
exposed and developed "with precision" to get negatives rich in tonality.
It is unforgiving in that regard and an improper exposure and/or processing
combination
will give you nightmare negatives. I still get nightmare negatives but
these days it is from the exposure and subject material rather than from a
processing problem.
The Jobo is totally repeatable and consistent and eliminates the variables
associated with negative processing. The totally uniform skies across the
entire negative is
always a delight to see.
Jobo expert drum for 4x5 model: 3005 (I think)
Drum rotation speed: 50 rpm, Solution volume: 240ml (solutions are
discarded after use i.e. one-shop processing)
No Prewet.
Processor: Jobo Atl-3
I am using the Atl-3 processor, and I love it, since I can load it and walk
away
from it. It has made large format photography fun for me. Jobo has a more
affordable model CPE-2? processor that you have to have to time manually.
I have
used that processor too and, with the expert drums, it will produce negatives
identical to the automated Atl-3. But that model always worked better for
me when I played some favourite CD's while using it.
If you are serious, and you are developing 4x5 frequently, and you want
more time
to make images, then you can't beat the Jobo and the expert drum combination.
But it is an *expensive* combination especially the automated Atl versions.
I was fortunate to purchase mine at an auction. This equipment appears in
the used market from time to time and this makes the cost of ownership a
bit easier. For those folks who are on a tighter budget, I understand that
the BTZS tubes are an excellent way to develop 4x5 sheet film for zone
system work and are available from a company called Darkroom Innovations.
I think a set of BTZS tubes are around $100 US.
Jobo also offers a compact processor the Atl-1000. Although it has many nice
features the expert drums are too big for this processor.
Judy, I hope that my recipe for "perfect" negatives is helpful.
Best Regards to all.
Robert Hudyma, e-mail: rhudyma@netcom.ca or rhudyma@aol.com
Semi-Tech Corporation, 131 McNabb Street Markham Ontario Canada L3R 5V7
Phone: (905) 475-2670 ext: 228