Developing time using Jobo 3*** drum

[Songyun]

I was reading the DDX tech info on ilford website regarding developing time. It suggests that with the continuous agitation the development time will be reduced by 15%. Does anyone follow this suggeston?

[Bjorn Nilsson]

In general the dev time for Expert drums are somewhat shorter than the times suggested by the manufacturers. 10-15% reduction is a good starting point. But please do your own tests. There are reports about some dev/film combinations where there is no change in time at all. It's possible that this is due to most of the drum is still filled with a lot of air, which makes some developers oxidize a bit quicker. On the same note, the Expert drums uses quite small amounts of developer, which in turn exhausts the dev more and quicker (than e.g. a CombiPlan or Paterson).

//Björn

[Bruce Watson]

What Bjorn said. Different developers respond differently to continuous agitation. More active developers seem to react badly to continuous agitation. Their development times become unworkably small.

I used to use HC-110 to develop 5x4 Tri-X. I found I couldn't control it with a Jobo CPP-2 and a 3010 drum. Not even dilution H. At five minutes, with a presoak no less, at 20C and 30 rpm, the film was still to contrasty and highlights too dense. Like developing everything at N+1 or more, with no way to get down to "N."

My solution was to move to XTOL 1:3. Less active, reasonable development times, and the ability to establish a real "N" development time.

The real lesson for me was, you have to do the tests. You have to establish your own personal EI with your developer and workflow, and you have to establish your own personal "N" development times with your developer and workflow. It's just testing you have to do yourself if you want control of the process.

[ic-racer]

If a film manufacturer does not give a rotary/continuous time, then 15% decrease is reasonable place to start for condenser projection printing. If you are printing with diffuse light, try your first test with the standard time.

Also, Jobo indicates that with some films a pre-soak will retard development by about 15%, again indicating non-rotary time would be a good starting point (if you want to use a pre-soak).

[Don Dudenbostel]

I use Ilford HC and have to dilute 1:47 and run the 1:32 (B) times or less. Once in a while for one film I use D-76 at reduced times but find the results with both developers to be excellent. If you find the times too short even at higher dilutions try reducing the temperature.

The Jobo seriously agitates the process. I had a Merz twin tube machine and a Colenta rotary machine in my studio for many years and never experienced the extreme degree of agitation with either machine that I do with the Jobo. Even with this heavy agitation it does a superb job.

[venchka]

What everyone else has said: Personal testing is the only way. I started with Xtol 1:3 and Kodak's time for HP5+ of 12:15 in a Jobo 3010 on a Beseler base at about 30 rpm. I am down to 9 minutes.

[Arne Croell]

Since Wayne mentioned rpm: Although any reasonable rotation rate could be named "continuous agitation", the rpm you use still have an influence, so stay with one rotation rate when you do the testing and for the negs after that.