View Full Version : Jobo 2850 print drum

20-Feb-2014, 21:08
Hello all...first official post for me!

I have a few questions about Jobo 2850 print drum. I am still very new to all this printing stuff and this is my first time using rotary processing, so if my questions are stupid, please bear with me! :)

- Jobo states that you only need 200ml of solution to develop paper in this drum...is there a minimum amount of developer you have to use (like the 100ml of minimum developer per film reel when using extol)? I searched around but didn't find anything.
- I am using Ilford Multigrade developer. Ilford states that you can process 50 8x10 FB in 1000ml of developer. Do that means that I can do 10 FB in my 200ml? Or should I do less than that for constant results?


21-Feb-2014, 05:42
You should be alright with 200 ml of diluted developer in the jobo drum, also because paper developer is a lot more active then film developer. But to be sure you can run a simple test. Take a negative with a lot of dark tones. Make 2 identical prints, using the same exposure and gradation. Develop one with 500 ml developer, the other one with 200 ml. When they come out the same, you will know you're safe.

It is my understanding that fiber based paper uses about 30% more developer, but in principle your calculation seems to be right. Personally i would be weary using paper developer to the maximum capacity, afraid of loosing the deep blacks in the shadows. I would make a bit more - let's say half a liter - and use that as a stock for the whole session and then toss it when i am finished. It is cheap enough, compared with the efforts of making prints.

There are certain risks in developing fb paper in drums. The paper sags when it gets wet and might collaps in the drum. Others state that sticks tot the wall of the drum and is very hard to get out. The risk for this is considerably bigger for large sheets of paper, but you'll find out soon enough by trial and error. For RC-paper drums are great!

21-Feb-2014, 10:04
Thanks for you reply! I will try your suggestion of using 500ml instead. 200ml for the whole 2850 drum seems so little.

2-Mar-2014, 16:16
I regularly use 300ml of paRodinal 50+1 for 3 minutes for paper negatives, but I suspect I could use less. For ra4 process, I use 150ml of tetenal ra4 developer. Hope that helps.