How do you know when to stop reusing a developer?

[dcy]

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.

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.

 

[dcy]

This is not true. In Thornton's Two Bath developer, substantial development does take place in the first bath.

Ok. Then I will stick to the standard advice. I've seem from a couple of different sources that if I make 1L of Part A and 1L of Part B, they're both good for 15 rolls and then I toss them out. I won't try to adapt it to smaller volumes.

 

[relistan]

@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.

 

[Don_ih]

I long ago concluded reusing developer was a bad idea. I use a few developers and generally only 1-shot.

However, I replenish D76. I mix 1 litre of stock and 500ml of replenisher. Most of my rolls are short (around 18 exposures) so I put in about 20ml of replenisher every time after developing a roll (you put replenisher in the developer bottle before pouring the used developer back in). Once the 500ml of replenisher is gone, I use the D76 one-shot or 1:1 until it's 3/4 gone and dump the rest. I also sometimes pour off 500 ml of the replenished developer and add 500ml new developer to that to make new stock. You want to avoid the sludge at the bottom of the bottle.

Anyway, you get a lot of film developed from that. Way more than any other use of D76. Replenishment is like restoring your developer after every use.

But don't developer Tmax in that. Tmax outright murders it.

 

[dcy]

@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.

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.

Ok. So here's the story:

The reason I am making this developer is that my partner wants it. A few days ago I was chatting about all the stuff I've been learning lately and I talked for a bit about how two bath developers work. That really grabbed her attention and she asked me to make her that. She shoots color film and sends it to the lab. She shoots a fully automatic camera with AF and auto-everything. 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.

You've been very helpful, and I hope you won't mind me asking you to hold my hand a little bit more here.

 

[snusmumriken]

@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.

 

[pentaxuser]

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.

Can anyone say where this 60ml of developer comes from? Is there something about 2 bath developers that causes 60 ml to be absorbed each time

When I do one shot development and then pour it down the drain I can't be sure how much less developer there is but I feel sure that a lot less than 60ml is "missing" so to speak out of 240ml for a 35mm film in a Jobo tank.

Thanks

pentaxuser

 

[dcy]

Can anyone say where this 60ml of developer comes from? Is there something about 2 bath developers that causes 60 ml to be absorbed each time

@relistan said 20ml

 

[dcy]

@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.

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.

Question: You said you also replace the baths if the date on the bottle is a long time ago. At what age do you think a bottle should be replaced even if I haven't used it much? My understanding is that D76 and D23 stock solutions last 6 months, so I imagine it's the same for Part A.

 

[Yezishu]

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.

 

[Raghu Kuvempunagar]

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.

Exactly.

 

[RalphLambrecht]

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 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.

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.

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.

I applaud your use of one-shot developers. It's the only way to get consistency into film development. I'd do the same with the things you want to try.

 

[RalphLambrecht]

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.

precision is the enemy of close enough

 

[RalphLambrecht]

I can do that! Let's hope I never accidentally pour the fixer in first.

You can't recover from that but if you kept the developer,atleast you got 'free' developer for the next roll.

 

[Yezishu]

I wonder how different the concentration of metol will be after each succesive film?

Engineers in the industry love this! They calculate how much bromine and iodine are introduced with flim, how much developer is used, and how many byproducts the emulsion carries away. Then they add replenisher to keep the composition in the developer tank stable in processing several thousand feet of film. The developer is designed to work under some byproducts. However, we are not processing at industrial level......

 

[relistan]

@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.

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.

 

[relistan]

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.

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.

 

[Raghu Kuvempunagar]

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? After all you need to get two solutions to the same temperature every time you want to develop, store two solutions in air tight containers, check regularly for loss of activity or increased activity, agitate intermittently while keeping track of time, and find the right development times for every film by testing.

 

[Don_ih]

How is it simpler and more fool-proof than, say, Rodinal 1+49?

It isn't. A one-shot liquid developer will always be the simplest and most foolproof.

 

[dcy]

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.

Thanks. At least now I know. I'm going to make 1L, take some easy precautions like using distilled water and suitable containers, and monitor the progress.

 

[dcy]

How is it simpler and more fool-proof than, say, Rodinal 1+49?

I don't want to get into a debate over this. She is familiar with Rodinal 1+49. The perceived advantages of the two bath are:

(1) That you use nearly the same time for any film --- John Finch says 4min for ISO 100 film and 5min for ISO 400.

(2) That it's a compensating developer. You are less likely to overdevelop or blow the highlights.

(3) That the final result does not seem to depend too strongly on some of the variables you listed. John Finch has an interesting video where he increases the time in bath A by +50% and +100%. Only when he doubled the time in bath A did we feel that the image got clearly worse.

In any event, you don't have to agree. You can just accept that other people may see this and feel that it looks more fool-proof. If you are right and Rodinal 1+49 is the way to go, we will discover that soon enough. We do have Rodinal at home, and I will be experimenting with one-shot developers --- including PC-TEA 1+50 and D-23 1+1. So she'll easily get to see if my film development is consistently better than hers in a way that she cares about.

 

[dcy]

@relistan : I am starting to read the thread you linked to, and I just came across this:

Distilled water is basically impossible to buy here.

!!!!!

Could this be a key factor in the discrepancy between those who report 12 rolls and those who report 3 rolls?

I buy distilled water at the grocery store for $1.26 / gallon. I use it exclusively for everything except rinsing.

 

[Alex Benjamin]

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.

You're actually simplifying things, which is what should be done .

This is an unbelievably simple developer to use. Make one litre of A, one litre of B, develop 12-15 films, discard, make more.

With each film, or films, I develop, I put back the used A and B back in their respective 1 litre bottle so that whatever carryover there is from A in B gets diluted. I've never bothered to re-mix bath B until my 12 films are done. Never had a problem.

The tricky part with TTB, as with any two-bath system, is controling contrast through development time in bath A. But if you follow the general instructions,and use as a starting point 4 minutes in each bath for slow film and 5 minutes for 400 ISO films, you'll be fine.

 

[snusmumriken]

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.

Thanks for this, Karl. I had forgotten about the thread you linked to, even though I posted to it, several years after it started!

As you say, the images @gorbas posted there were made using BT2B that had already processed 10 rolls, ie at the point where even I would feel I was approaching the limit. He also said that, despite that finding, “ I can not see any negative effect of it on developing film”.

@Alan Johnson also noted in that thread that given a chance (time, airspace), the metol carried over to Bath B will oxidise and become inactive. It’s certainly the case that Bath B can become quite a vivid orange after a few rolls of film/weeks - but as already said, I’ve found that it works nonetheless.

 

[Sirius Glass]

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.

The storage sealing is important to keep oxygen out of the developer. Some people use wine bags. I have found the that StopLossBagsTM when use with their funnel [to minimize spilling] have worked for me for years. I have gotten my replenished XTOL to last more than two years. I always use a 35mm piece of film to test the developer before using. www.StopLossBags.com