Rodinal 1+100 - Enough for two 120 rolls in one tank?

[marcmarc]

Hi Everyone,
I've got a dilemma I hope you can help me out with. I've done an enormous amount of shooting last year and I have a freezer of about 50 120 rolls of exposed film. I've been getting up extra early to develop a roll before I head out to work and then I soup another roll when I get home in the evening. However, I'm still shooting a lot so it seems like my freezer is 2/3 full with film all the time. So I want to start developing two 120 rolls in a tank. I usually use a steel 16oz tank for a single roll. I have a taller steel tank that will hold two 120 reels and one 135 reel (as a spacer) on top. I find that 800ml of solution will cover the reels and still leave (I hope) enough space above for adequate agitation. Has anyone used Rodinal 1+100 for two rolls? I know there are those that feel 5ml of rodinal isn't enough for one roll but I like the results I get with Pan F+ and Acros 100 at this dilution. I use standard agitation - constant agitation for the first minute, then several inversions every 30 seconds. I've had problems before developing two 135 rolls in the past however. I was souping two 135 rolls of Tri-X in HC-110 I+50 in my 16oz tank. I would often get built up density along the edges. With some advice I learned that I was filling the tank to the brim which was defeating the whole point of agitation. I worry though that the bottom roll will get less agitation then the top roll. I also have an issue of "Darkroom Photography" from the 1980's in which a pretty thorough test of agitation was carried out on 100 rolls of Plus-X and D-76. I have to dig up the issue but I seem to recall that the test results proved that developing multiple rolls in a single tank can create problems with streaking, uneven development etc. So I'm reluctant to try this until I hear back from some of you more experienced folks. The impression I got from the artical was that in general, it's safer to develop one roll per tank at a time. However the thought of getting 4 rolls developed per day rather then 2 is very appealing to me. So in nutshell:

1) Can I use Rodinal 1+100 for two 120 rolls? If not will I get the same results at the 1+50 dilution for two rolls that I would get with one roll at the 1+100 dilution?

2) Can I use 1+100 for two 135 rolls in a 16oz tank or would the taller tank be a better choice. I understand that a 135 roll and a 120 roll is the same area of film, but the taller tank will give more room for agitation.

Once I catch up on this backlog of developing, I'll probably go back to developing single rolls at a time. For now though I just want to be able to put food back into my small freezer! Thanks for replies.
Regards,
Marc

 

[NB23]

1+100 is one ml of Rodinal per 100ml of water.

Divide the ml capacity of your tank by 100 and that's how much Rodinal you will need to mix with one-hundred times the amount of water. Do the mix and fill your tank. Do the cha-cha-cha and voila, your film is developed!

It's really that simple.

 

[pekelnik]

I just want to point out that you can usually put two 120 films on one reel, so you might be even able to develop 3 or 4 in the larger tank, but I have no idea if 1+50 is enough for that.

 

[EASmithV]

So long as you use at least 10 ml of developer. I just processed 3 rolls or 135 using 1:100, with 10 ml dev to 1L water.
You need at least 5ml per roll of film. This is why I love my Paterson tanks, I can cram enough chems in them for them to work, unlike Hewes or Jobo.

 

[Terry Christian]

Also, to help avoid uneven density, make sure you are agitating gently. A slow rocking motion to redistribute the liquid in the tank is enough - a developing tank is not a cocktail shaker.

 

[EASmithV]

Also, to help avoid uneven density, make sure you are agitating gently. A slow rocking motion to redistribute the liquid in the tank is enough - a developing tank is not a cocktail shaker.

Wait till laundry time and put it on the dryer

 

[marcmarc]

Hey good idea EASmithV...then I don't have to hang 'em up to dry! OK so for two 120 or 135 rolls, 10ml to 1000ml will give me the 1+100 results I'm after. I think for the 135 rolls, the taller tank might be better since the 16oz tank doesn't leave a lot of space between the top reel and the bottom of the lid for sufficient agitation. After I learned from my previous mistake of filling the tank to the brim, I could readily see the difference sufficient agitation makes. Thanks again everyone for taking the time to give me advice.

 

[Leigh B]

Regarding developer capacity:

The datasheet says 10ml of Rodinal concentrate per "roll" of film, regardless of what dilution you choose.

In this case a "roll" is defined as any combination that could be proofed on a single 8x10 sheet of paper, i.e. one 36-exposure roll of 35mm, one 120 roll, four 4x5 sheets, or one 8x10 sheet.

One 220 film would be two "rolls".

- Leigh

 

[Thomas Bertilsson]

You need at least 5ml per roll of film.

This is the culprit. When you dilute to 1+100 you use a lot less concentrate. This may well mean that you simply don't have enough developer concentrate to fully develop the film if you put two films into the same volume of developer.

In order to guarantee the same results while developing two rolls as you get developing one, you must double the volume of working solution. Make sure you have a tank that can hold that amount of developer - or else you may get inconsistent results.

Why not 1+50? Developed to the same contrast index, I challenge you to show me much difference between 1+100 and 1+50.

 

[baachitraka]

I personally never recommend 1+100 unless you really know what you want at that concentration.

 

[dario]

As has been said, the critical factors are quantity of developer concentrate and agitation. If you double the quantity of developer concentrate when doing two films and use a tank that gives similar agitation you should be OK.

I use a 3-reel Paterson tank and 500ml of solution for a single 120 roll. Using the 3-reel tank ensures that the developer drains right out of the film with each inversion of the tank. (A 2-reel tank may be adequate, but I had a 3-reel on hand, so I use that.)

This complete draining may not be critical with 120 film. With 35mm, it avoids the the problem of uneven density around the sprocket holes, as discussed in the Darkroom Photography article, and it seems not illogical to apply the same technique to 120. If nothing else, it’s nice to visualise the film inside getting an even dose of fresh developer with each inversion of the tank.

If I were developing two rolls at once (which I don’t), unless the tank is big enough that both rolls drain, I’d be concerned that the two rolls were not getting identical treatment. I might be being unnecessarily sensitive on this point, but I’ve read comments about Rodinal being more sensitive to agitation than some other developers, and experiment seems to bear that out.

I used to use 1+50 Rodinal, with “normal” agitation (30 seconds of gentle inversions, then four inversions each minute) and closely controlled time and temperature, but had trouble with the highlights becoming too dense. Densitometer measurements confirmed that the curve was running away (curving upwards) at the right-hand end. And this result seemed consistent with advice from a mentor to agitate very gently.

I experimented with greater dilutions, less agitation (30 seconds of gentle inversions, then two gentle inversions every three minutes), and longer times (about twice as long as before). From successive experiments, I found I was developing to exhaustion: more time did not increase the contrast further. And the results were what I was seeking: a smooth curve that was straight at the higher densities (did not curve upwards).

With this latter procedure, 1+80 is now my “normal”, and I use greater or lesser dilutions to get more or less contrast. It seems to work well for me. The technique is similar in principle to using two-bath developers.

I’m religious about maintaining the temperature at 20 degrees. But, because I’m developing to exhaustion, I suspect that temperature is less citical, although I haven’t established it experimentally.