Jobo 25xx tanks and roller base

[XRe]

Question regarding the Jobo roller base and their 25xx series tanks... Will the 2521 actually fit on the roller base, or is it too short? What about the 2551? I'm finding it hard to determine from their website... (well, the Omega-Satter website, anyhow...)

 

[Jerry Thirsty]

I can't say specifically about either of those two tanks, but the two bases can be slid along the rods until they butt right up against each other. I would guesstimate that they are about 10cm from end to end at that point. Also, the clip that supports each roller can either be pointed in or out, to deal with large and small tank diameters.

 

[Shmoo]

The 2521 is a bit too short for the roller base...it's awkward. The 2551 is fine and can also be used on the Beseler motorized roller as well. I have both drums, the roller base, and the Beseler...never use the 2521 or the roller base any more.

 

[jstraw]

I have a question about translating developing times to the continuous agitiation of a roller base. Is there more developer activity due to constant agitation or is it offset by the fact that the emulsion is only submerged part of the time?

If I need to shorten development, is there a formula or rule of thumb?

 

[bdial]

Yes, you do need to reduce the time due to the constant agitation.
Ilford says to reduce times up to 15%, Kodak also publishs rotary processing times. Jobo also has some guidelines.

 

[jstraw]

Thanks. I'll google for Jobo's numbers.