Motor bases: How important is reversing?

[sienarot]

I finally got around to getting a Beseler motor base off eBay and boy developing's never been easier! I don't know why I didn't get one sooner!

Anyways, the Beseler 8921 I picked up is unidirectional. I figured just flipping the tank around every once in a while should be good enough to compensate for this. I did my first two runs (c-41) with the new base last night, flipping the tank every minute. The negs came out great and evenly developed (my whole reason for moving up to the Jobo/Beseler system).

But now I'm wondering, am I going a little overboard with the reversing? Is reversing even necessary for even development? I pre-soaked my negs for 5 minutes (also with reversing) just to make sure they're all nicely coated and swelled with liquid before it's time to add the developer. It'd be nice to just let it run while I step away for a few minutes until the next step.

I'd like to hear your experiences on this.

[BarryS]

My motor base only rotates in one direction and I've never noticed any problem with uneven development. That's with Pyrocat HD and b&w film, and I like to optimize development times to over 10 minutes. I always start with the simplest procedure and see if i have any problems before making things complicated. Truthfully, I think most presoaking is a waste of time (ducks and covers).

[venchka]

I developed 14 sheets of B&W film in 4 runs between Sunday and last night. In a Jobo 3010. On a Beseler base. All turning in the same direction. No worries. No problems. I adjust the leveling foot on the base to keep the 3010's open end slightly high. The lid rides against the drive wheel on the base and the 3010 doesn't walk off the base. Very secure. I tried flipping once. The lid was "downhill" and the tank tried to walk off the base. Never again.

YMMV.

[Jan Pedersen]

My beseler is running in one direction but i do flip both the 3010 and the 3005 every one or two minutes. I have not noticed uneven development but had problems with clearing the negs running only one direction. Since i started flipping the tank i have had no problems.

[venchka]

This is a classic "Ask 10 people and get 20 answers" question.

[Bruce Watson]

All I can tell you is that a CPP-2, running about 30 rpm, reverses about 8-10 times a minute. It's cycle seems to be about 2.3-2.5 revolutions, then it reverses. I've read that part of the reason to do this is to break up laminar flow over the film. I'm guessing that this can cause something like bromide drag marks if left unaddressed, but I've never done any research to try to find out.

But does it matter in practice? Too many variables to be able to guess at. So, like most things in LF, try it and see. If it works for you it works for you. What do you care what anyone else thinks if you've got prints you're happy with on your walls?

[D. Bryant]

This is a classic "Ask 10 people and get 20 answers" question.
The problem of streaking when using a Beseler drum on a uni-direction base has been discussed quite a bit over the years. So it is a real issue especially if a Besseler drum is being used. The suggested solution was to change to a bi-directional base or flip the direction of the drum 180 degrees during the development cycle.

Don Bryant

[Glenn Thoreson]

My motor base has off set wheels that rock the drum, in addition to rotating. I've never seen another one like this. It only turns one way. I've never had a problem with uneven development in a Unicolor print drum. If it weren't for the rocking motion, I would definitely reverse the drum a few times per cycle.

[Greg Blank]

In testing and repairing the CPP2 processors, I believe the bi-direction rotation when using Expert Drum is detrimental to the reversal circuit. The original design of the Jobo was for the bi-directional microswitch to be used for paper drum not the Expert Drums the design predates the Expert drum. The design of the Expert drums causes the bi direction surface flow of chemistry, regardless of the motor reversing. I have processed film both ways and there is no apparent difference to me. However I will say that over time due to the relay switching the motor polarity that under load of a fully loaded 8x10 drum something will die. The design of the circuit ramps power to keep the motor speed consistent as load is increased. Eventual a component or multiple components burn out.



All I can tell you is that a CPP-2, running about 30 rpm, reverses about 8-10 times a minute. It's cycle seems to be about 2.3-2.5 revolutions, then it reverses. I've read that part of the reason to do this is to break up laminar flow over the film. I'm guessing that this can cause something like bromide drag marks if left unaddressed, but I've never done any research to try to find out.

But does it matter in practice? Too many variables to be able to guess at. So, like most things in LF, try it and see. If it works for you it works for you. What do you care what anyone else thinks if you've got prints you're happy with on your walls?

[sienarot]

Thanks for the feedback everyone. It's comforting to know reversing isn't absolutely critical for even development.

[Dirk Rösler]

Thanks for the feedback everyone. It's comforting to know reversing isn't absolutely critical for even development.

It was for me with 8x10 in a 3005.

http://www.largeformatphotography.info/forum/showthread.php?t=44572

[Benno Jones]

My Beseler base is uni-directional as well. After reading about experiences with streaking, I just started off flipping my tank every 5 minutes on long development times and 2 minutes on short development times. For things like fix and permawash I flip it once in the middle. No problems with streaking, but then I've never done it without flipping the tank so I can't say I would have streaks without...

I also have trouble with the tank sliding off to one side, so I just put my film washer next to the motor base to keep the tank in place.

[Greg Blank]

There are a lot of factors why someone might get streaks unrelated to to bidirectional rotation. How the chemistry is poured, whether the developer is properly mixed. What type of developer can also be one factor. Whether one used enough solution, and whether was level, the Expert drum "is" designed to give bidirectional agitation regardless of if a motor reverses the drum. I have a completely clear 3010 that one can see that the chemical sloshes in multiple directions when placed on the Jobo.

The whole idea is that the chemical is displaced from top cylinder to the lowest, and in circling the chemistry sloshes back and forth and side to side in a given cylinder.

Not saying your experience is invalid. Just that used that way intended there should be no streaks....regardless of motor or hand reversals or none.




It was for me with 8x10 in a 3005.

http://www.largeformatphotography.info/forum/showthread.php?t=44572

[mandoman7]

There are a lot of factors why someone might get streaks unrelated to to bidirectional rotation. How the chemistry is poured, whether the developer is properly mixed. What type of developer can also be one factor. Whether one used enough solution, and whether was level, the Expert drum "is" designed to give bidirectional agitation regardless of if a motor reverses the drum. I have a completely clear 3010 that one can see that the chemical sloshes in multiple directions when placed on the Jobo.

The whole idea is that the chemical is displaced from top cylinder to the lowest, and in circling the chemistry sloshes back and forth and side to side in a given cylinder.

Not saying your experience is invalid. Just that used that way intended there should be no streaks....regardless of motor or hand reversals or none.

I have a CPP2 and hadn't heard this before, but it makes sense. I've noticed that if I move the white crow's foot out of the way (at the drive gear) it stays unidirectional. Is it your suggestion that the motor will last longer if I leave it this way? Like the other poster said, its good to simplify my procedures, and if it preserves my motor then all the better .

JY