The developers I'm asking about are D-76 and Thornton's 2-Bath. I gladly accept your suggestion to RTFM for D-76, but for Thornton's, I have not been able to find a FM that I can consult for this information.
The answers to your questions is once again, "It depends" ...upon which developer you are asking about! Storage is generally discussed in the directions for use.
This is not true. In Thornton's Two Bath developer, substantial development does take place in the first bath.
@dcy It doesn’t matter that much how much volume you have in bath B (within reason), if you add 60ml of bath A it’s going to develop film fairly well. So, no, 3 uses of any size bath B is where the behavior starts to become noticeably different. It could be even worse with 500ml. I have not tested that small. But honestly, trying to get 15 rolls from 1L of A is taking IMO l risks with your output. As Raghu says, bath A DOES develop film fairly well in this developer. There are threads showing this. So it will be noticeably more exhausted by that point.
If you want to experiment with how many rolls you can develop with the same times and how far you can stretch it, by all means have at it. Maybe you’ll learn something you can report back on. But I suggest not to try that with anything you care about.
Second, if each film absorbs 60ml, then after 12 films there should only be a third of the original 1 litre volume left. What I observe is about two-thirds still left, so I don't think the amount absorbed can be 60ml per film.
No no, I'm glad you chimed in. I think this is helpful. John Finch from "Pictorial Planet" had the same experience you did. I don't understand why there's such a discrepancy between people who are happy putting 12 rolls through each bath and people who feel Bath B should be replaced after 3 rolls.@dcy, @relistan: I'm reluctant to complicate things, but I have used BT2B for quite a few years now, and until last year when I read comments here on Photrio I always developed at least a dozen 36 exp rolls in 1 litre of both baths, though I replaced them anyway if the date on the bottle was embarassingly long ago! Nowadays I still do about a dozen rolls in 1 litre of Bath A, but I replace Bath B after 4 or 5 rolls. I do this because the comments about carryover spooked me, but honestly in my previous regime I never noticed any difference in performance as the film count went up, except that the developer could be quite 'hot' for the very first film. I guess that's because the breakdown products of development - which are inhibitory - are absent at first. Make of all this what you will. The stuff is cheap to make, so probably it is prudent to change the solutions quite often.
It’s normal to have some Discrepancies. Developing 12 rolls in one morning or just 3 rolls over a month, ambient temperature, storage containers, and water source—can affect the outcome. Other’s experiences can be very helpful, but them don’t guarantee exactly the same results.
I am mainly interested in one-shot developers precisely because I want to avoid the complexity of having to figure out when it's OK to reuse a developer, or whether I need to extend the development time or something. Having said that, for my edification, how would one go about deciding when to stop reusing a developer and make a new batch? A couple of concrete examples come to mind:
I'm wondering if perhaps I can do a "clip test" like the one you use to test the fixer. Like... I could cut a piece of exposed film, put in a beaker, and when it takes longer than X minutes to turn pitch black, it's time to change the developer.
- I plan to use D-76 1+1 one-shot, but I'd love to try D-76 stock to see about that finer grain.
- I plan to use D-23 1+1 one-shot, but I'd love to try Barry Thornton's 2-Bath developer just to see what it's like.
On the topic of Thorton's 2-Bath developer, the published recipe is for making 1L of Part A and 1L of Part B. Would I be right to assume that it's totally fine to make smaller quantities (e.g. 500 mL Part A + 500 mL Part B) as long as I can fully submerge the film?
EDIT: PS --- I know I can't do smaller mixes of D-76 because the powder you get from Kodak is heterogeneous.
It’s normal to have some Discrepancies. Developing 12 rolls in one morning or just 3 rolls over a month, ambient temperature, storage containers, and water source—can affect the outcome. Other’s experiences can be very helpful, but them don’t guarantee exactly the same results.
I can do that! Let's hope I never accidentally pour the fixer in first.
I wonder how different the concentration of metol will be after each succesive film?
@dcy, @relistan: I'm reluctant to complicate things, but I have used BT2B for quite a few years now, and until last year when I read comments here on Photrio I always developed at least a dozen 36 exp rolls in 1 litre of both baths, though I replaced them anyway if the date on the bottle was embarassingly long ago! Nowadays I still do about a dozen rolls in 1 litre of Bath A, but I replace Bath B after 4 or 5 rolls. I do this because the comments about carryover spooked me, but honestly in my previous regime I never noticed any difference in performance as the film count went up, except that the developer could be quite 'hot' for the very first film. I guess that's because the breakdown products of development - which are inhibitory - are absent at first. Make of all this what you will. The stuff is cheap to make, so probably it is prudent to change the solutions quite often.
I'm sorry if this next bit is off the original topic of the thread, though it seems very relevant to the questions you (@dcy) ask in the last few posts. It is really addressed to @relistan, who I think has tested this experimentally. I'm not questioning whether Bath B becomes a developer in its own right, because I haven't done such experiments. But first, Bath A obviously gets smaller with each roll developed because it is absorbed into the dry emulsion and is carried over into Bath B. A fair bit of development takes place in Bath A, so I accept that inhibitory breakdown products will accumulate there, although some will be absorbed into the emulsion of later films along with the developer, so it's not like they accumulate only within what is left in the bottle. I wonder how different the concentration of metol will be after each succesive film? Second, if each film absorbs 60ml, then after 12 films there should only be a third of the original 1 litre volume left. What I observe is about two-thirds still left, so I don't think the amount absorbed can be 60ml per film. Third, by design, most of the developer carried over into Bath B will be exhausted within the emulsion during its time in Bath B, also creating more breakdown products. So it's not like you are simply dropping 60ml of fresh Bath A into Bath B.
Honestly there’s no right answer like with most things. Make 1L and try it on a few experiments until you know how it works. See what happens. If you want some safety margin, use A for like 6-8 rolls and replace bath B after 3-4 uses. If you want more economy, it seems some folks have luck with much more, so try it further and see.I do not want to experiment or test the limits. I would be immensely grateful if you could give me specific advice of how much Thornton Part A and Part B to make and how often to replace them and I promise to follow it to the letter.
The relative simplicity and "fool proof" nature of a 2 Bath is what made her decide to try to develop B&W at home. I want this to go well for her. I do not mind replacing the baths often.
How is it simpler and more fool-proof than, say, Rodinal 1+49?
Honestly there’s no right answer like with most things. Make 1L and try it on a few experiments until you know how it works. See what happens. If you want some safety margin, use A for like 6-8 rolls and replace bath B after 3-4 uses. If you want more economy, it seems some folks have luck with much more, so try it further and see.
How is it simpler and more fool-proof than, say, Rodinal 1+49?
Distilled water is basically impossible to buy here.
I'm reluctant to complicate things, but I have used BT2B for quite a few years now, and until last year when I read comments here on Photrio I always developed at least a dozen 36 exp rolls in 1 litre of both baths, though I replaced them anyway if the date on the bottle was embarassingly long ago! Nowadays I still do about a dozen rolls in 1 litre of Bath A, but I replace Bath B after 4 or 5 rolls. I do this because the comments about carryover spooked me, but honestly in my previous regime I never noticed any difference in performance as the film count went up, except that the developer could be quite 'hot' for the very first film.
I think you misread a little if what I was saying. It’s roughly 20ml of carryover per roll. The 60ml is from three rolls. There are lots of things going on when you reuse a developer, including restrainers contained in the emulsions of some films. It’s hard to say what the limit is. But if you are getting repeatable results, carry on! My caution was for someone new.
I used this developer a lot in the past but did not do extensive testing here on carryover but @gorbas did some testing and shared his results. This was the result of a 1L Thornton developer that had been been used for ten rolls. https://www.photrio.com/forum/threads/advice-on-my-two-bath-developer.181701/page-7#post-2423623
I am looking for the other thread where he did specific carryover tests but have not found it in a few mins of searching. Perhaps you can find it.
Anyway, in the above you can see that both baths (not just A) are reasonably good developers on their own after some rolls.
My own carryover experiments were pretty extensive but focused on PC developers where the problem is much worse.
The answers to your questions is once again, "It depends" ...upon which developer you are asking about! Storage is generally discussed in the directions for use.
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