How often should rotary agitation reverse?

[williaty]

I'm bodging together a rotary agitation setup for processing 4x5 and 120 film. I've got a Jobo tank and a Color by Beseler roller base. Given the diameter of the Jobo tank, the Beseler roller base reverses direction every 1 and 1/8th revolution. So at least it's making a bit more than a full revolution before reversing. This seems a bit fast to me (compared to experience a decade ago with an actual Jobo processor). Will this work or does the tank really need to run in one direction for longer than that?

 

[MattKing]

What developer and film will you be using, and what is your average projected development time?

 

[williaty]

Developer will be XTOL 1:1. Films are whatever I have at the moment but probably a lot of HP5+, FP4+, TXP, Acros 100. Times as listed by Massive Dev Chart until I get my own testing done and modify them.

 

[Vaughn]

I prefer longer -- and my 3005 drum did not make a full rotation on my Unicolor, so I disabled the reversing mechanism and turn the drum 180 degrees every minute of so.

 

[Rick A]

Both my Uniroller bases run about four seconds, approximately 1 1/3 revolution before reversing.

 

[Sirius Glass]

My 135 and 120 film in 1500 tanks are run at the 'P' speed, while the 4"x5" in the 3010 Expert Drum are run at '4' speed.

 

[Kawaiithulhu]

disabled the reversing mechanism and turn the drum 180 degrees every minute

I did exactly the same - both 4x5 and 120 (Xtol and pyrocat-HD) and I've not seen any problems. If the development is shorter than 6 minutes or so I flip the drum at 30 second intervals just because.

 

[bvy]

I'm also using the Unicolor reversing motor base for 120 with XTOL 1:1. I'm finally getting good even development. Worth nothing that I'm still using a small stainless steel tank. I don't put it on its side, but rather upright in a large drum. So, in that sense, it's like constant hand inversion.

 

[drpsilver]

16 June 2016

I use a 2551 tank on a Beseler motor base, but have never used the reversing feature (which now does not function). I will allow the tank to rotate in one direction for 50 seconds then invert/rotate the tank 7 times to mix chemistry. After this I will then place the tank on the motor base so it will rotate the opposite direction for 50 seconds. Repeat this process for the allotted development time. Most of my development times are less than 10 minutes for the films mentioned above. I use this agitation routine for all chemistry: develop, stop, fix, and HCA. I only process 4x5 sheets using rotary methods, 120 (and 35mm) are processed in a small tank. My developer of choice is D76 (1:1).

It took a little testing and experimentation to get development times that gave me good negatives (for my process). I have had good results with the above process - uniform development, no air bells, and no agitation marks. I should note that I do not use all six slots that are available on the reels. I only use the inside and outside slots on each side of the reel (thereby only 4 sheets per reel). I do this because if the sheets are too close to each other there is the possibility of inadequate agitation between sheets.

Hope this helps.

Regards,
Darwin

 

[Xmas]

When I use my little Agfa daylight loader only ever turn it in one direction.
When I use plastic reels I normally use stand.

 

[ChuckP]

What does the Jobo Processor do? I thought it was 2 revolutions but I'm not 100% sure.

 

[williaty]

I thought it was closer to 10-15 seconds before reversing. Of course, it's been 15 years since I've worked with one.

The quick reversing of the Color by Beseler base does not appear to be causing problems (so far).