Processing two 120 films on a single universal reel ??

[old school]

As its possible to process a 220 film on a universal reel, and a 220

film is approximately twice the length of a 120 film, it must be

possible to fit two 120 reels on a single reel. Does anyone do this

(to double the number of films processed in same quantity of

chemicals) and if so, is there an obvious/easy technique for getting

both films on the reel without one overlapping the other, and how do

you subsequently get them off.

 

Thanks

 

Stuart

[gerald_widen]

Not familiar with the 220 film but if it is just twice the length of 120 just cut the film in half and wind balance on another reel and develop in a taller tank. Or just do the film twice. All you would lose would be one shot or none if you just had the film blank on shot #13 and cut there.

[david_goldfarb]

Gerald, I think he's asking about doing two 120 rolls on a 220 reel, rather than processing 220.

 

There are people who do this, though I don't do it myself. If you wanted to try, I'd practice with the lights on using a test roll, then in the dark, just like learning to load a reel in the normal way. If you wanted to be really ambitious, I've also heard of people loading two rolls of film on the same reel back to back, so you could conceivably fit four 120 rolls on a single 220 reel.

 

Don't do this, though, with a very dilute developer, like PMK at the normal dilution or Rodinal 1+100, or it will be exhausted before the film is developed.

 

SS tanks being cheap these days, I just have various sizes, so I can do up to six MF reels in my largest tank, which seems about right for the amount of processing I do. After a longish trip, I might have four batches, but that's not such a frequent occurrence.

[robert_davis2]

I'm not 100% sure what a universal reel is. Patterson? With the Jobo reels they have a little clip you push into place after the first roll. That keeps the two rolls apart. Shouldn't be too hard to figure out something similar for your reel.

[old school]

David, I am asking about two 120 films on the same reel. I think the main problem I can foresee is when the first film passes the ballbearings on the reel and so is no longer being pushed on the reel. The only two methods I can think of are 1) to manually push the first film further onto reel once past ballbearings, but with this comes the possible danger of kinking the film or damaging the lower layer of film with my finger as I push the trailing edge of the film, or 2) taping the two films at the join (maybe even use the tape that attaches the film to the backing paper?) but wasn't sure what the chemicals will do to this or other tapes. Anyone with any experience of doing this? or anyone who has tried the back to back method?

 

As a rule of thumb when working out chemical quantities to ensure that the developer doesn't become exhausted during development (processing two 120 films instead of one) should I stick to the same volume of chemical to film area ratio that I use for 35mm (or should there be enough spare capacity in the developer i.e. that the volume suggested on the tank for each film size is to ensure full film coverage in the tank rather than to avoid exhaustion of the developer?

 

Thanks

 

Stuart

[old school]

Robert, how does the Jobo clip work? does it clip to the reel or the film?

[titrisol]

I don;t know if this helps, but I used to do 2 35mm in the same spiral by using a piuece of masking tape to stick their ends and then feed them into the spiral as one "thick" film.

 

Make sure the base sides are together and that the emuslions have good access to the developer and use about 50% more fluid than for 1 roll alone.

[robert_davis2]

The clip is on the reel. It's just sticks down a little when closed.

 

http://www.jobo-usa.com/products/2500.htm#Other%202500%20Series%20Pictures

 

The red thing on the black reel. It's hard to see in the picture.

[stephen hazelton]

I notice when I put 120 film in those reels, it is on the outer part of the spiral, and when I get done developing, it is on the inner part of the spiral. So I think you'd need some way to keep the films from migrating where they overlap.

[jay_de_fehr]

Yes, I do it all the time. Just use a small piece of tape to join the ends after the first roll is wound on. It can save a lot of time/chemicals if you have a lot of film to develop with a few reels, especially since the plastic reels must be COMPLETELY dry to get the film on.

[__hank_boneroneo1]

I'll try it the day after I use leader-out rewind.

[john_stockdale2]

The Jobo clip does work well. They give instructions on their web site about how to do it. I tried it and it worked fine, first attempt. Without such a clip, a method of stopping the films moving and overlapping seems to be essential, even for inversion processing.

[peter zisson]

I do this routinely with 120 on Patterson reels. I use the tape that attaches the second roll to the paper backer. Not only have I not had the tape come loose during processing, but it still holds well enough after processing to hang the film as a single long roll.

 

A slight (up to an inch or so is as far as I have gone) overlap where the two films join does not seem to have any negative effect while loading the reel. The most important thing is to get both films aligned so that the second is not canted to one side. Hence the slight overlap, which makes alignment easier.

 

Peter

[jay_de_fehr]

Peter is right on the money. To make sure the rolls align, I put the tape on the first roll, sticcky side up, and roll it onto the reel, past the ball bearings, then slide the second roll on and attach it to the first. No problems, ever.

[rahul_deshpande1]

So assuming I'm able to get the 2 rolls on 1 reel, do I use the same dilution of chemistry or double?

[frank.schifano]

It's best, I think to follow at least the manufacturer's recommended minimum of developer per roll of film. In Kodak's technical publication J109 for XTOL, they specifically recommend an absolute minimum of 100 ml of STOCK developer for each 80 square inches of film. I suspect the same is true for D-76, though Kodak does not specifically mention minimum amounts in their J78 publication for that product.

 

That 80 square inches works out to 1 roll of 120 or 135/36, 4 sheets of 4x5, or 1 sheet of 8x10 film. In my experience Kodak's number is an absolute minimum, and one that is not always sufficient to insure complete development. Because a roll of film with a high percentage of "high key" exposures will have more silver halide that must be reduced to metallic silver than will a roll with a high percentage of "average" or "low key" exposures, the developer will exhaust more quickly. To insure that your developer does not exhaust prematurely, that minimum should be increased by at least 50%. My personal minimum is 150 ml. per 80 square inches of film. For two 120 rolls, you'll need double the amount of developer at your usual dilution rate or the same volume of developer at 1/2 your usual dilution rate. Either way, you'll be using twice as much stock solution.

 

Knowing that, why bother trying to fit two rolls onto one reel in the first place? That's asking for difficulties at best, bad results along with wasted film and chemistry at worst. A two reel SS tank complete with reels can be had for not much more than the cost of a half dozen rolls of film these days on the used market. If you have a few bucks to spend, $50 US will get you a Paterson tank capable of handling up to five 120 plastic reels at a time from B&H or Adorama. Generic plastic reels (which work fine and will fit the Paterson tank) can be had for $7 US each from the same place. You might even know some people who would be willing to part with some unused darkroom equipment for a song rather than go through the trouble of listing it on Ebay. It pays to ask around.

[rahul_deshpande1]

Your ending comments make a lot of sense. I went ahead and souped 2 rolls on 1 reel with the same dilution of HC110. No development problems, though the tape that connected the 2 rolls slipped midway and completely destroyed one frame which had the most "bang-on" exposure of the Manhattan bridge.

No more experiments :-(

[richard_trochlil]

Well, gee, for 30+ years I have been doing thusly with Patterson reels.

 

1. Be sure everything is completely dry. Run the first roll in. After it passes the detent balls, continue the ratcheting action while lightly pressing alternately with your fingers moving the film until the end passes three times. When the right side ratchets forward, your right hand fingers should be pressing the flim, then the left side etc.

 

2. Then put the other roll in normally.

 

Never had a problem.