Roll Film AGITATION - Thornton's Two Bath
I have been working with Thorton's Two Bath Developer (120 roll film on stainless reels) for the past couple of months. I have had excellent luck so far and am settling into an agitation pattern. I have The Edge of Darkness and have done quite a bit of "web" reading on this developer.
I am especially curious about how others are agitating their roll film on stainless reels. This seems to be where the biggest variances occur.
Also, I have been experimenting with Barry's N+ recommendation of a bath B using 20g of Sodium Metaborate instead of the normal 12g. (I have not yet needed an N- that the normal processing didn't handle). When using these variations, are you sticking with your normal agitation or changing that as well?
Thanks for your input.
Just out of curiosity, what differences do you see at N development when you change agitation?
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I suppose since I am asking others to share their agitation schemes and thoughts for Thorton's Two Bath the least I could do is write out and share how I am currently doing things.
I set up a 1 liter measuring cup almost filled with distilled water and one drop of LFN wetting agent - Bath A solution is in a two (120) reel tank filled just over halfway (600ml) - Bath B solution is in a two reel tank filled just over halfway (600ml) - a 1 liter measuring cup filled with tap water for a quick water stop - then another 1 liter measuring cup with fixer.
My film is loaded on a Hewes reel with a stainless lifting rod, processing one roll at a time. I pre-soak for 2 minutes and let drip for 30 seconds.
I then start Bath A with 1 minute of agitation. Agitation is done by lifting the rod up so the top of the reel meets the top of the tank and then setting it back down. After 3 up and downs I rotate the tank a few degrees. After the first minute I repeat with 3 up and down motions every 30seconds followed each time by another slight rotation of the tank.
I let it drip for 15 seconds.
I then start Bath B with 15 seconds of agitation. Agitation is done in the same style as Bath A except that I agitate only at the top of each minute instead of every 30 seconds.
I let it drip for 15 seconds and then 15 seconds in the water stop with agitation the entire time, again by lifting the reel out of the solution and setting it back in.
From there I go into the fixer.
I plan to do some testing with less agitation in bath A (and using a bath B with less Sodium Metaborate) for more extreme N- situations but have not yet done so.
Last edited by Shawn Dougherty; 08-19-2013 at 06:57 PM. Click to view previous post history.
Originally Posted by Thomas Bertilsson
I have seen the biggest difference in the highlights when I agitate more or less in Bath A. Very little change seems to occur when I agitate more or less in Bath B.
Of course this is to be expected, Thornton's being more of an afterbath type of developer than a true two bath developer (a true two bath developer being one in which almost all of the development takes place in the second bath.)
This is why I am planning on testing the N- version (7g of Sodium Metaborate in Bath B instead of 12g) with reduced agitation in bath A as well. Maybe once a minute instead of every 30s. Of course I will work through those variables one at a time.
So far I have found I get nice, very printable results with my N process from a moderate N+ through a moderate N- scene. (I should add that I have been bracketing one way. An exposure at what I think is best and then an exposure one stop below that. I was doing a third exposure one stop above metered at first but found that was never the exposure that printed best. I should also add that I tend to expose generously in the first place.)
Last edited by Shawn Dougherty; 08-19-2013 at 10:09 PM. Click to view previous post history.
I was hoping to do some testing on this but just haven't had enough time lately. But here are some initial thoughts.
I'm not entirely convinced by Thornton's line of reasoning regarding changing contrast by altering the amount of alkali in bath B (ie altering pH). Of course, what we need to know first is if development in bath B is to exhaustion with the N formula and time. Typically with two-bath/divided baths development is assumed to be carried out to exhaustion in bath B. Suppose this is the case. Then suppose the only thing you change vs. the N-process is to increase the Metaborate concentration to 20g/L. It seems to me all this would do is increase the rate of development in bath B. Why would it increase contrast? You've still got the same amount of bath A absorbed in the emulsion as in the N process, which places a finite limit on the amount of reduction which can take place in bath B. So from a tonality perspective wouldn't you just get the same result, only faster? The only mechanism I can think of which might lead to a small increase in contrast with more Metaborate (or a decrease in contrast with less Metaborate) is the relative resistance to the decreased pH associated with the buildup of acidic development by-products. Perhaps that is what is happening. Not sure if the effect is significant as Metaborate is a somewhat buffered alkali.
The conventional way of altering contrast with this sort of developer (ie where there is activity in bath A) is to simply alter the time and/or agitation in bath A. At least on the surface of things, this seems like the most logical approach to me. I also think it would be the least risky from a uniformity perspective (for increases in contrast), and should be the most consistent from an image structure perspective. Increasing the pH of bath B can only make it harder to achieve uniformity as development in bath B is fast. The many threads/discussions with Sandy King regarding divided Pyrocat allude to this issue. Regarding image structure, varying the pH of bath B can also affect graininess - even if there is no change in contrast. Not that graininess is bad, and in medium/large format it might be invisible anyway. Just asking the question.
I suppose the best thing would be to try what Thornton says and see if it works as expected.
One thing that surprised me in your description is the use of a pre-soak.
Can't really comment on the agitation technique per se since I've never tried it. But what you're doing with the separate tanks is a good idea particularly for bath B. Pouring/dumping would definitely increase the probability of getting unevenness in bath B where development is rapid. If you're getting even development, stick with what you're doing.
Last edited by Michael R 1974; 08-19-2013 at 09:15 PM. Click to view previous post history.
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What you're saying makes sense to me. I have definitely determined that I can affect the density of the highlights through normal time / agitation changes in Bath A. (So far I have kept the times for Bath A and Bath B the same for simplicity sake.)
I have only processed two rolls of N+ thus far. With the first roll, all I changed was the amount of Sodium Metaborate in Bath B. I did not see much of a contrast increase over what I metered. No prints yet, but the highlight densities are not what I would normally expect from N+ development.
With the second roll I increased the Sodium Metaborate AND increased the development time by 1 minute. This roll looked like a normal N roll, so there was a definite increase in the highlight density from what my meter showed.
This would seem to support you theory. (Though I do not have a densitometer I believe I have enough experience to judge whether or not there was an increase in the highlight densities based on how I metered the scenes, at least with a non-staining negative.)
For my next N+ roll I plan to use the the normal amount of Sodium Metaborate in bath B and simply increase the time by 1 minute. If that works, the next time I feel I need a lot of expansion I will not only increase the time by one minute but agitate more frequently as well.
When next I encounter a scene which requires serious N- development I will try decreasing the time, and for the second roll decreasing the time as well as the agitation in Bath A.
I will say that there does indeed seem to be some compensating effect in the normal procedure, as I mentioned I have exposed moderate N- scenes on the same roll as N scenes and moderate N+ scenes and come away with negatives that print more easily that when I did this with other developers (which happened frequently with my Rolleiflex T as there is no ability to change backs).
As far as the Pre-Soak...
My main reason for doing a short presoak is to remove the AH dye. I have been running 8 rolls through 1 liter of Bath A (Thornton suggested 15 was possible so I thought I'd be conservative. It's pretty cheap stuff even at 8 rolls). 8 rolls worth of AH dye in the developer would be quite messy. I'm not sure if that would matter but it would certainly make it difficult for me to see if there were particles or foreign objects in the developer. I let the negatives drain off water for 30 seconds and shake them a bit during that time. Also, my N time for HP5+ has been 5 minutes so I assumed that in that amount of time there would be plenty of chemistry absorbed by the emulsion.
Last edited by Shawn Dougherty; 08-19-2013 at 10:08 PM. Click to view previous post history.
I consider the inventors of Diafine to be the experts on two bath developers. Baumann was the company that did the research and popularized this development method. They recommend 5s of gentle agitation initially and then 5s every minute. They warn that too vigorous agitation will result in loss of shadow detail. Two bath developers are all variations on a theme and they are more similar than they are different. Development is a diffusion controlled process and too much agitation will only cause problems.
Last edited by Gerald C Koch; 08-19-2013 at 10:46 PM. Click to view previous post history.
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Originally Posted by Gerald C Koch
Could you elaborate a bit? 5s initially and then 5s every minute... Does that apply to both Bath A as well as Bath B?
I really don't see the point with agitation when using thornton. To maximise edge effects, less is more. It is like the perfect stand developer; the stuff is not in the soup long enough to get the normal bad effects from stand. Yes, I do give a 30 second fierce shake ending with a firm tap to lodge the air bubbles. But that is it.
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I also realize there will be many that can't let go of the agitation, but the results are fantastic.
A nice side effect of this is the dev times get closer together, thus harder to screw up.
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The point of agitation is to control development thus affecting tonality in a predictable way.
For me personally, well, my negatives are plenty sharp, I'm not looking for edge effects. I'm only making contact prints so even if they weren't very sharp they would be sharp enough. I've had enough experience with stand development to realize it is not for me. Reduced agitation to help control an extremely high contrast scene is one thing. I just don't believe stand development is a good general purpose development method.
Even Gerald's suggestion of only 5 seconds of initial agitation makes me a little nervous. =)