8x20 JOBO processing
I'm going to do my first run of 8x20 today. It's HP5+ and I'm going to run it on the JOBO using the 3063 drum.
I'm wondering if I dare put two 8x20's in this drum which is designed to take 1 16x20. I test-fit a sheet of film in there, and it seems like there's plenty of room...one thing I'm concerned about though, is the film popping out of the groove and ending up sitting flat in the center of the drum.
Any advice/suggestions for processing in this tank? Should I do them one sheet at a time?
I'm going to go with a standard developer and take away 15% of the time to compensate for the rotation development.
Any advice about that?
What are you printing on?
I've been finding out recently how inherently low contrast FP5+ is.
I'm going to start with gelatin silver paper...ILford MGIV.
I've been developing FP5+ in a tray with HC110B. Normal development times give pretty flat negatives. Moderate over development doesn't seem to change this.
That's all I know for now, I have to do more research.
Run your Jobo at the slowest possible setting, below the F(or P, whatever that first letter on the rotation speed dial is), just before it turns off. Then you can use the normal development times for whatever developer you're using. Even if they come out a bit contrasty, you can always print with a Grade 1 or Grade 0 filter using VC paper. HP5+ is not as responsive to expansion/contraction development as other films, even FP4+, so you can overcook it a bit without being too worried about the highlights getting blown out.
Oooohhh, excellent advice. I'm heading into the darkroom now. I think I'll do an old sheet of 12x20 first to see how it goes.
The man I bought my 7x17 camera from did not use a Jobo. It has been a few years but if I remember correctly he said he got marks bleeding through from the ribs that run around the 3063 cylinder. I have never tried my 7x17 film in a 3063 because of that.
Instead I use 2560 and 2830 tanks connected. Two sheets of film fit into the lengthwise ribs with enough tension to keep them in place. There is only one circular rib in the middle and it does not leave a mark. Perhaps there is another tank combination that would accommodate 8x20 with ribs at 8 inches. The combined tanks are 21 inches deep.
I use Bostick & Sullivan's rollo pyro developer on HP5+, FP4+ and T Max 400. There is a 5 minute prewash then the developer, speed setting "4", 68 degrees F, and dump at 6 minutes. It takes about 20 seconds for the developer to pour out and another 20 seconds for the first water stop to get in, so development is really longer than 6 minutes. I have been adjusting all this for about four years. Good luck. Hope that helps.
Too bad the USA Jobo reps didn't continue to build the vacuum-formed inserts.
But there is a way to build a similar insert --
Get some flat carpet runner (not the one with the pegs on the backside to prevent slipping).
Go to a stationary store and get some binder posts -- get the short ones. These were used to bind papers using a 3-hole punch. You may have seen them - a flat screw that goes into another screw-like section, with threads inside the tube.
get some RTV.
Use an electric drill to make holes for the binder posts -- screw them in. Put a little RTV on the backside where the post comes through to hold papers using a 3-hole punch.
Like the Jobo inserts, the pins go along both sides of the long direction of the sheet, and on the ends of the sheet locations, BUT you need to make it longer than the sheet -- slightly, so the carpet runner insert can by wound up into a cylinder and shoved into the 3063.
Now you have something similar to the insert sheets that Jobo created.
Kudos to Rod Klukas for this idea. (I haven't had to resort to this as I have a pair of the jobo 7x17 and pair of the jobo 12x20 inserts, but thought I'd post this here to help others).
....now you can build an insert for the 3063 for 2 8x20 or even 3 7x17.
Don, sounds very interesting. I would LOOOOVE to see a pic of that. Remember, I'm a photographer (i.e. visual learner). :D
Michael, I've developed multiple sheets of 7x17 successfully in a 3063 without having them pop out of the ribs. But it may depend on the exact measurements of the film.
The usual caveat applies - my negatives, developed in D-76, are clean, but people who use staining developers have reported unevenness attributed to the ribs.