View Full Version : More stupid questions about jobo expert drums

Robert Coenen
21-Jul-2006, 07:17
I appologize for possibly missing this in another thread but I am new to the world of Jobo and the expert drums (just got a 3010). And I wanted to utilize a Beseler motor base that I have had lying around for too long.The first of my questions is this: What is the proper number of rotations per minute for the drum? The drum instructions state 50, I have seen in posts that people are hand rolling 40, and when I time the motor base that I have it is giving me 32. Any help on this would be greatly apriciated.

And for my second question: Are the instructions correct for the expert drum (3010) it only requires 210ml (just under 8 ounces) of chemicals?

Thank you for your time, Robert

Jorge Gasteazoro
21-Jul-2006, 07:43
It does not really matter, as long as you are consistent with your development. Before I was able to buy a CPP2 I used the besler motor base with great success. The only thing you have to watch out for is the drum creeping off the base, they do it even when you try and level the base.

Yes the solution quantities are accurate if you are using the Jobo base, I would use a greater amount if you plan to go with the slower besler base, you have nothing to loose but a few pennies on developer...

Good luck.

Bruce Watson
21-Jul-2006, 07:47
For rotation I use the lowest speed with which my Jobo CPP-2 is stable - about 30 rpm. The CPP-2 reverses direction after just a bit more than two revolutions. I suspect your 32rpm should be just fine.

As to volume of chemisty, the 210ml is the minimum amount required to cover the film. You will probably want to use a little more just to be safe, unless you are sure your drum is perfectly level. In addition, you'll need to make sure you include enough chemistry to get the job done.

For example, using XTOL you need 25ml of stock per sheet of 5x4 Tri-X. Or, for 10 sheets, 250ml of stock. I use XTOL diluted 1:3, so it takes 1000ml (250ml stock + 750ml distilled water to dilute the stock). In this case, 1000ml of XTOL 1:3 is the minimum needed to get the job done.

Ron Marshall
21-Jul-2006, 08:01
I spoke on the phone with a Jobo technician some months ago who told me that Jobo had increased the recommended minimum volume to 330 ml. However, a friend of mine, and I assume many others, has always used 210 ml as his minimum. I usually use dilute developer so I am always above 330 in any case.

Robert Coenen
21-Jul-2006, 08:20
Thank you for the info and your time. I have always used tray or BTZS tubes for processing so exausting the developer was never a problem. Because I was processing small batches and discarding the developer after the first use. I think that I will use the same quantity of developer that I used for the BTZS tubes (2 ounce per sheet). That should keep me covered.

Artur Zeidler
21-Jul-2006, 08:33
I have never bothered to work out what the rotation speed was on either a beseler or a unicolor base. It seems slow enough and works ok.

As above, there is the minimum amount of developer volume the tank needs to work, but each developer also has a minimum volume to work per sq in of film - that can vary enourmously and you need to check the developer information.

As for the creeping, one thing that helps is a couple of big thick (as thick as those you get on brocolli) elastic bands. One on each end of the tank, just outside each of the base rollers. This helps, although it doesn't always prevent creep.

21-Jul-2006, 14:37
If you are planning on usig PyrocatHD or other staining developer formulated for rotary development you will probably want to rotate even slower. I was using a base for some time with Jobo drum, finally gave up because of problems with temperature control. Now I rotate by hand in a tempering bath. I usually rotate some 10rpm - even with such slow rotation it gives very even development.
BTW - some time ago I had a problem with some areas in the negative apparently not receiving chemistry. With the help of contributors to this forum I sorted it out and now I am using 500ml instead of volumes suggested by Jobo. Also be very carefull when loading film and follow exactly Jobo instructions.