Paterson Orbital: seeking advice on modifications for sheet film processing

[Gabe]

I recently snagged a NOS Paterson Orbital, which I plan to use for processing 4x5 sheets (especially semi stand, which it seems particularly suited to). I have read around a bit already regarding modifications others have made (Regular Rod's little guide was particularly helpful).

I have already removed the plastic "wings" on the sides of the lid light trap, and for sheet separators have fashioned some tall posts to replace the stubby red studs the tank comes with. These posts I made from 2mm diameter acrylic rods tightly sheathed with silicone rubber tubing; they then fit the holes quite snugly and with good friction from the rubber to keep them in place. Replacements could be easily made if needed.

The final mod still to be decided on is a good solution for raising the sheets off the tank floor (to prevent incomplete washing of the anti-halation layer, and sticking of the sheets to the tank). I would prefer to avoid permanently scoring or gouging the tank floor as I have read others doing. I had the idea to use some tiny (6 x 2mm) domed rubber bumper pads for this purpose (the kind you put on cabinet doors etc to stop them banging). I plan to remove the thin layer of crap adhesive these come with, then glue them permanently into the tank using epoxy resin.

Has anyone else tried this approach?

One slight nagging concern I have is that the rubber has a bit of friction to its surface, with an ever so slightly tacky feel to it, so I'm wondering if sheets might stick in place to the pads during processing and cause incomplete washing of the sheet in those areas, which would defeat the purpose. The total area of contact with the dome tips is very small, so I'm probably worrying about nothing on this point. Another possible long term problem however could be degradation of the rubber via contact with the processing solutions.

Any thoughts or advice? Thanks in advance.

[CreationBear]

It sounds as if you're sorted--I've only used my Orbital for 5x7, but haven't had any problems with the "domes" you mention, though I do occasionally manually test them to see that they're still adhered before beginning a run.

Otherwise, the only thing I might be doing differently than you might be my use of a water bath; following a tip from Eric Searing, I've also gotten into the habit of replenishing my Pyrocat HD mid-run to make sure I've enough chemistry for the emulsive surface area I'm working with.

At any rate, my next frontier with the Orbital is to try to get some "alt-able" 8x10 negatives--I'm a bit chary of getting surge marks if I get too burly with the agitation, but time will tell.

[Gabe]

It sounds as if you're sorted--I've only used my Orbital for 5x7, but haven't had any problems with the "domes" you mention, though I do occasionally manually test them to see that they're still adhered before beginning a run.

Otherwise, the only thing I might be doing differently than you might be my use of a water bath; following a tip from Eric Searing, I've also gotten into the habit of replenishing my Pyrocat HD mid-run to make sure I've enough chemistry for the emulsive surface area I'm working with.

At any rate, my next frontier with the Orbital is to try to get some "alt-able" 8x10 negatives--I'm a bit chary of getting surge marks if I get too burly with the agitation, but time will tell.

Thanks for the reply.

Good to know you've used the rubber domes with success. No long term issues with use of pyro then (hardening/cracking of the rubber etc)? I also plan to use Pyrocat-HD with my Orbital... maybe some 510-Pyro as well.

Yes I'd read about people sitting the tank in a water bath for longer developments. Something to consider. In terms of avoiding developer exhaustion, I'd planned to use 500 mL of 1+1+100 Pyrocat-HD, which should manage four 4x5 sheets I think. I know half the point of using the Orbital is to keep volume of chemistry low, but the pyro is so economical anyway I don't consider it a priority.

[mpirie]

Likewise, my Orbital has the rubber bumpers arranged so i can do 4x 5x4 or 2x 5x7 sheets at a time.

For the dividers, i glued some 1 inch plastic "tiddlewinks" to the top of the dividers to stop the sheets floating up and crossing into other sections.

I also float mine in a tray with water slightly warmer than 20˚C. I think you may be surprised that 500ml won't be enough to cover 2 sheets of 5x7 if you plan to do stand development. I filled mine up with water and measured the volume at around 800ml to cover the sheets!

Mike

[Gabe]

Likewise, my Orbital has the rubber bumpers arranged so i can do 4x 5x4 or 2x 5x7 sheets at a time.

For the dividers, i glued some 1 inch plastic "tiddlewinks" to the top of the dividers to stop the sheets floating up and crossing into other sections.

I also float mine in a tray with water slightly warmer than 20˚C. I think you may be surprised that 500ml won't be enough to cover 2 sheets of 5x7 if you plan to do stand development. I filled mine up with water and measured the volume at around 800ml to cover the sheets!

Mike

Thanks for the response.

OK that's two. I feel much more confident going ahead with the mod now.

[CreationBear]

Out of curiosity, am I right in assuming that everyone lets the tank dry completely between runs before adding another sheet(s) of film? I tend to Zen-out when using the Orbital (especially with a water bath) so I don't mind inefficiency, but I'm starting to wonder why I have more than one DDS film holder...

[mpirie]

Yes, i make sure mine is fully dry before reloading the Orbital.

It reduces the risk of getting marks on the film. I still pre-wash before adding the developer.

Mike

[CreationBear]

Excellent, thanks Mike--I'd considered trying to speed up loading in my
Harrison tent, then immediately adding the initial water soak, but given I'm bouncing around the house (no dedicated darkroom) that seemed a bit hectic.

[GoodOldNorm]

So what developers, amount of developer, agitation routine, development times and films are you using processed in the Pattison Orbital?

[CreationBear]

Norm, I'm still a newbie but I've found the Orbital lends itself to semi-stand/minimal agitation regimens pretty well. FWIW, for "scan-able" negatives, I use pretty dilute Pyrocat HD with FP4+, agitating for a minute or two at the beginning, then a couple of times (~10 seconds) more spaced in what's usually a 25-35 minute run. I've also seen gents who go the Caffenol approach for times approaching an hour.

On the other hand, there are a number of folks who seem to have experienced bromide drag and/or surge marks whilst going this route, so that's something you might consider too.