How to develop 20 x 24 film?

[biggerthebetter]

Sounds like a dumb question, eh?

I am considering buying a 20 x 24, and do not have a lab that can process 20 x 24 in Bangkok (where I live). Any suggestions on how I can do it myself in a borrowed darkroom? big trays? Or is there any cool gizmo to buy that can help?

I worry about developing in trays, due to trying to get developer to flow across such big sheets looks tough.

Any suggestions would be helpful.

Thanks - Pat

PS: I normally shoot 8 x 10.

[Ken Lee]

I have never developed anything larger than 11x14, but it occurs to me that short developing times would exaggerate any tendency for uneven or poorly controlled development. Thirty seconds difference, is a fairly small fraction of 10 minutes, but a large part of 5 minutes.

So if being in a warm climate, you can't keep the developer cool, then dilution might help. I presume that pre-soaking would also help prevent uneven development.

[sanking]

Sounds like a dumb question, eh?

I am considering buying a 20 x 24, and do not have a lab that can process 20 x 24 in Bangkok (where I live). Any suggestions on how I can do it myself in a borrowed darkroom? big trays? Or is there any cool gizmo to buy that can help?

I worry about developing in trays, due to trying to get developer to flow across such big sheets looks tough.

Any suggestions would be helpful.

Thanks - Pat

PS: I normally shoot 8 x 10.

One method is to develop the film in one of the 20X24" drums that were originally designed for making color prints, with continuous rotation on a Unicolor or Besesler motor base. This is a very efficient method as you only need about a liter of developer solution for a sheet of 20X24" film, and after the film is placed in the drum everything else can be done with the lights on.

The disadvantage is that you can only do one sheet at a time, but the practicality of using a 20X24" camera is that it is rare to make more than two or three negatives in a shooting session. And developing film is one of the smaller of the challenges you will have in working with a camera this large.

Sandy King

[c.d.ewen]

Pat:

One option is to use big Jobo drums in your bathtub. The 3063 drums will take a single sheet of 20x24. I develop two 12x20 negs at a time in Jobo 3063 drums.

As Sandy points out, drums are most economical. Using 16x20 trays, I use at least two liters of solution in each tray just to cover. Using drums, you'll have to pay attention to the quantities of solution, e.g., the 3063 needs a minimum of 300ml to cover, but the motor can't handle more than 1000ml. Check your favorite developer's minimum concentration - 20x24 is 240 sq inches, equal to six 8x10's.

Here's a minimum space, minimum $$ solution: semi-stand develop with Rodinal. I did four 12x20's last night, filling two 3063's with 16.5L of water and 80ml of Rodinal - 1:200. Lots of benefits: lights-on processing, do as many sheets at a time as you have drums, no need to buy the machine, just the drums, no need for split-second timing or temperature worries. No need to borrow a darkroom either. After draining the developer, smaller quantities of stop bath and fix can be used if you hand roll the drums.

Charley

ps: Cultural awareness note: I don't know if Bankok is like Tokyo, where a bathtub in a residence is a rare commodity indeed.

[biggerthebetter]

Team:

Great replies, very fast and really helpful.

Thanks,

[AF-ULF]

I develop my 20x24 inch negatives in the big Jobo drum on a CCP-2. You do not need the processor, however. You can use the drum in a tub as mentioned above, or on the Jobo roller base and roll it by hand. I would get two bases, one for each end of the tube. One roller base would probably work, but I think two would make the rolling much less taxing.

One caution with the Jobo drum is that it has ridges on the inside, which can cause lines on the negative with some pyro developer formulations. I use D-76 and have never had a problem with lines on the negatives. The ridges are nice to have because they allow fixer to get to the back side of the negative. With some of the non-Jobo print tubes you have to finish fixing the negative in a tray to get the back of it clear. I use 1 liter of D-76 1+0 per negative.

I have read that you can use the Jobo drum on Bessler motor bases, but I have never tried it. I would check to make sure it works before buying.

[Tracy Storer]

I process mine in open trays, 4-6 sheets at a time. I use a large volume of HC-110 developer, which I keep and replenish. Working this way is best done in a very long sink, mine is a home-built, plywood and fiberglass (marine epoxy) 12' long by 30" front to back. I have an also home-built ventilation system at the back of the sink to draw fumes away from me and out of the room. (I find the film strength fixer irritating to my throat otherwise)

[c.d.ewen]

I process mine in open trays, 4-6 sheets at a time.

......

In an open tray, I screw up two 12x20's at a time.

Charley

[biggerthebetter]

Tracy: I assume you use trays in this long sink (12 foot x 3 foot!!). Or, are you saying you develop in the largest tray in the world?

If you are using trays in the sink, what size? where do you get them? I see Calumet has 20 x 24 trays, but I obviously need slightly bigger (to get the fingers in there).

I am still intrigued by the Jobo system, but a little worried as I wanted to use Pyro and I repeatedly here of various issues with Jobo tubes and Pyro.

[Monty McCutchen]

Tracy: I assume you use trays in this long sink (12 foot x 3 foot!!). Or, are you saying you develop in the largest tray in the world?

If you are using trays in the sink, what size? where do you get them? I see Calumet has 20 x 24 trays, but I obviously need slightly bigger (to get the fingers in there).

I am still intrigued by the Jobo system, but a little worried as I wanted to use Pyro and I repeatedly here of various issues with Jobo tubes and Pyro.

For my 20 x 24 work I have used both trays and the Jobo. When I am shooting lightly I usually use the Jobo as it is nice to be able to do other things in the light when you are processing. One sheet at a time though when I am shooting more heavily or am coming in off a trip where I have a stockpiled amount to get through is just too time consuming and therefore I use trays. I haven't mastered up to six yet like Tracey has (give me time Tracey give me time!) but I usually do 4 at at time. It seems to go pretty well. The advantage to the Jobo though is less developer which is mitigated some by doing several sheets at a time in the open trays.

I bought giant Hypo trays from Calumet. 90 bucks per if memory serves correctly. They are smooth flat bottomed with 4 or 5 inch lip all the way around. They are much stronger than a conventional tray and can hold the force of that much water/developer much better. Conventional trays will buckle on you fast with the amounts of liquid used. The inside dimensions are something along the lines of 27 by 22. Sorry I'm not near them now to measure them for you. They work great though for any 20 x 24 work that you have.

As to Pyro in the Jobo look up in the archives here as I am sure there are several discussions on this by those that have much more expertise than me but I use Rollo Pyro which was partly developed for just this purpose--Jobo use. I have had no issues. If you use the Jobo though on an actual Jobo motor base choose the SLOWEST setting of rotation and that will help take away the density lines mentioned in an earlier post, which can ruin a nice negative fast. Please don't inquire as to how I know this.

Good luck. 20 x 24 is a fabulous format when it all goes right.

Monty