Time adjustments for drum processing of prints

[rcam72]

Hello everybody.

I've recently started using a Jobo CPP-2 processor for film. Everything I read, from the Kodak data sheets on the film to the Jobo instructions, led me to adjust the developing time.

I can't seem to find enough info on prints to be able to come to at least a starting point, other than 46 sec @20C that Ilford recommends for for Ilford RC papers using 2000RT developer/replenisher and fixer/replenisher and mechanical development.

46 sec seems short, considering I'll be using Dektol and the adjustment for the film was only about 15% less than manual processing. The processor instructions didn't help and I couldn't find any posts here or at photo.net. Any suggestions as to where else to look? Also, are there any issues with Dektol in a rotary processor? Kodak doesn't mention anything about mechanical processing with Dektol.

Thank you,
Raul

 

[bdial]

Paper is usually developed to completion, and with constant agitation, so you shouldn't need any time adjustment.

 

[Ian Grant]

Paper is usually developed to completion, and with constant agitation, so you shouldn't need any time adjustment.

Paper isn't developed to completion, I'm not sure where you got that idea from.

Raul, the Ilford 2000RT developer isn't designed for rotary processing, it's designed forrapid processing in roller transport machines, you can use Ilford Multigrade or PQ Universal.

There's no real need to use the Jobo unless you really want to try to economise on developer, it's quicker to tray process.

Ian

 

[Bob-D659]

I use 90 seconds for 16x20 drum and tray processing for everything smaller with Dektol, I just make sure I really agitate the test strips in a small tray if I'm going to run a print thru a drum. Works for me.

 

[rcam72]

Ian, I referenced the Ilford 2000RT developer because it is the only one mentioned on the data sheet for mechanical developing. Thanks for the info though. I'm trying the Jobo for prints to see how it fits my routine of printing a lot at a time instead of a couple here and there.

Bob, thanks for sharing your experience. 90 sec sounds like a reasonable place to start.

Thanks all,
Raul

 

[Dave Starr]

I use my CPP2 for prints over 11x14, & let them develop for the same time I would use in trays - 2 min for FB & 1 min for RC.

 

[rcam72]

Bob and Dave,
I'm curious as to what speed you use for the agitation. I believe the manual calls for a setting of P.

Thanks,
Raul

 

[Bob-D659]

I use a Simma motor base, very much like a Beseler, except one of the drive wheels is eccentric so the drum "wobbles" end to end as well as rotating. A 16x20 Beseler print drum rotates 7.5 turns is 15 seconds including the coast to a stop. So I'd guess its 30 rpm give or take.

 

[rcam72]

Thanks Bob.

Unfortunately the CPP-2 doesn't provide wobbly agitation, I guess because it could eliminate the need for the $$ expert drums. I'll have to figure out the rpms for the different settings, or just go with the manual recommendation.

Being new to rotary processing I have to ask what I think may be an obvious question: How does higher rpm's affect the development of the print, or negative for that matter? I'm realize the time is decreased or there would be no need for differentiating between rotary and tray processing, but is the image affected at all, besides the patterns that can form from a lack of irregular flow? Is there such a thing as too much agitation?

Thanks,
Raul

 

[Bob-D659]

Well I also use 8x10,11x14 and the 16x20 drums for RA4 colour processing, 2 minutes at room temp, no matter what size of drum. They are all different diameters and will rotate at different rpms as the motor base has one speed, ON. I would just do a few with Dektol and see what emerges. Ilford 2000RT is a roller transport developer and it can run at a much higher temp than Dektol's recommended 20C, as automatic processors can only run so slow.

 

[Dave Starr]

Bob and Dave,
I'm curious as to what speed you use for the agitation. I believe the manual calls for a setting of P.

Thanks,
Raul

I use the P setting.

 

[rcam72]

Thanks for your responses everyone.

 

[Mike Wilde]

I have run Dektol 1:1 in a roller processor set up to run RA-4, at 30C, along with TF-3 at film stringth for fixer at 30C, and a rinse tank. Both active tanks provide 45 seconds of contact. The challenge with this set up is to deal with the volume of prints to wash, since the machine can process then as fast as you can expose them. The dektol is pooped after a few hours; this is where 2000RT developer would still be working and just would be replenished as you go.