Barry Thornton's two-bath question about time and temperature

Chuck_P · Jan 12, 2025

Alex Benjamin said:
That's how I read it. But I'll admit it's not clear.

Further down in the article, after giving the formulas for each baths, Thornton states "Try about 4 minutes in each at about 21º C for roll films; 5 for sheet"—which seems to imply that you should (or can) agitate after three minutes. But earlier, in the part I quoted, he indicates that "all development has ceased" after three minutes "or so". Now why keep the film in the developer for one to two aditionnal minutes if "all development has ceased"?

There are a few old threads on Dixactol on Photrio.

Maybe all the highlight development has ceased but the low and mid values continue some more, but then, that goes against "all development has ceased" comment. In The Negative, AA said a variation of the two-solution process, would be to develop the film to N-1 or N-2, which that in itself implies like you would in a single bath..............then, allow the film to "stand in the alkali bath for several minutes to reinforce the shadow densities." This implies to me that not all the development has ceased.

Alex Benjamin · Jan 12, 2025

Chuck_P said:
Maybe all the highlight development has ceased but the low and mid values continue some more, but then, that goes against "all development has ceased" comment. In The Negative, AA said a variation of the two-solution process, would be to develop the film to N-1 or N-2, which that in itself implies like you would in a single bath..............then, allow the film to "stand in the alkali bath for several minutes to reinforce the shadow densities." This implies to me that not all the development has ceased.

I ony have Thornton's Edge of Darkness. I think his earlier book, Elements: The Making of Fine Monoprints, has more info on this two bath process. Maybe someone who has it could chime in...

Chuck_P · Jan 13, 2025

Alex Benjamin said:
Further down in the article, after giving the formulas for each baths, Thornton states "Try about 4 minutes in each at about 21º C for roll films; 5 for sheet"—which seems to imply that you should (or can) agitate after three minutes. But earlier, in the part I quoted, he indicates that "all development has ceased" after three minutes "or so". Now why keep the film in the developer for one to two aditionnal minutes if "all development has ceased"?

I didn't check the link you provided until just now and noticed a descrepancy between what John Finch (YT: Pictorial Planet) said and what BT put in this particular article "Fine Negatives Automatically". Finch said BT's bath A, formulated for higher acutance, contained 6.5g of Metol and 80g of Sodium Sulphite (which is how I mixed it). I wonder if Finch is mistaken or did BT revise Metol down and SS up at a later date in some other article.

retina_restoration · Jan 13, 2025

Chuck_P said:
View attachment 387780

I didn't check the link you provided until just now and noticed a descrepancy between what John Finch (YT: Pictorial Planet) said and what BT put in this particular article "Fine Negatives Automatically". Finch said BT's bath A, formulated for higher acutance, contained 6.5g of Metol and 80g of Sodium Sulphite (which is how I mixed it). I wonder if Finch is mistaken or did BT revise Metol down and SS up at a later date in some other article.

There have been multiple tweaks to the BTTB recipe. The one you quote above is not the "final revision" version. The recipe Finch uses is the same one I have been using for a few years. I believe this is the one that was chosen as "final":

Bath A
Metol 6.5g
Sodium Sulphite 80g
Water to 1 litre

Bath B
Sodium Metaborate 12g
Water to 1 litre

That said, there is going to be VERY little effective difference between those two version.

John Wiegerink · Jan 13, 2025

Yes, I don't know if anyone could tell the difference. I drop the sodium sulfite to 75g and could see no difference. I don't care to use anymore SS than I have to.

Chuck_P · Jan 14, 2025

Here's a link to the article that I copied the below information from..............I found it on Unblinking Eye, you may already have it but it seems applicable to this part of the discussion. At the top of the link is a bit on how Joeseph Lipka used DD-23 for platinum printing.....it must require bullet proof negatives with the time and temps it mentions.

But, the pasted information below is from the article "Divided D-23" by Ed Buffaloe...........it does not mention BT but is the first reference to Divided D-23 and the use of TMax film that I found, specifically referencing the use of the B bath. I'm not sure when it was written but at least sometime after 2000.

"Pre-soaking in water is not necessary. Use your normal agitation method in solution A, and unless you want a very strong N-2 contraction, go ahead and give 10-15 seconds of agitation per minute (or more) in solution B as well. (For N-2, don’t agitate solution B at all.) Increasing the time in solution A raises overall density and contrast, whereas increasing the time in solution B will only raise shadow detail if the film is returned briefly to solution A first.

Jim Veenstra gives some suggested developing times in his article, and since the article is so hard to come by I am going to reproduce his suggestions here. You will note he considers that D-23 does not require the second bath with T-Max films except for an N-2 contractions".

Edit:

I realized the pasted chart was wonky, so here is a screen shot of it for quick reference:

Just to test the above times, I developed two 4x5 pinhole negatives in the standard Divided D-23 formula. The film was T-Max 400, rated at 320, developed for 7 minutes in solution A and 2 minutes in solution B at 68°F. The results compared quite favorably to my PMK negatives of the same subjects. I plan to use this developer in the future for N-1 and N-2 contractions."

John Wiegerink · Jan 14, 2025

That's interesting Chuck_P and I have never read what you link before. I have found that no or very little agitation in A bath is a NO-NO, but altered agitation in B bath is OK for different results in your negative, good or bad. I'm sticking to a normal agitation pattern in A and a very short Agitation at the beginning of B and then one half way through. Works good for now.

Igor_77 · Jan 14, 2025

John Wiegerink said:
Yes, I don't know if anyone could tell the difference. I drop the sodium sulfite to 75g and could see no difference. I don't care to use anymore SS than I have to.

I think that accuracy of less than 5% is redundant and not visible.

Alex Benjamin · Jan 14, 2025

From Edge of Darkness, which could be considered the final version.

John Wiegerink · Jan 14, 2025

Igor_77 said:
I think that accuracy of less than 5% is redundant and not visible.

That's what I found also. I just figured that since I am more of a medium format guy that if cutting back on SS increased grain slightly, which I haven't noticed, it wouldn't matter with the larger than 35mm negative.

Chuck_P · Jan 14, 2025

John Wiegerink said:
That's interesting Chuck_P and I have never read what you link before. I have found that no or very little agitation in A bath is a NO-NO, but altered agitation in B bath is OK for different results in your negative, good or bad. I'm sticking to a normal agitation pattern in A and a very short Agitation at the beginning of B and then one half way through. Works good for now.

That' interesting, I'm doing similar minimal agitation in bath B but haven't considered not agitating in bath A, and I will take your word for it. If you look at the article I linked to, the author suggests that it's not "really" a divided developer as he states: "My first thought when seeing the Divided D-23 formula was that it’s not really a divided formula at all (it’s D-23 with an alkaline after-bath)." In Schaefer's Book 2, AA does seem to differentiate between divided and two-solution methods of development. The process being talked about here seems more in the way of the "two-solution" process.

John Wiegerink · Jan 14, 2025

Chuck_P said:
That' interesting, I'm doing similar minimal agitation in bath B but haven't considered not agitating in bath A, and I will take your word for it. If you look at the article I linked to, the author suggests that it's not "really" a divided developer as he states: "My first thought when seeing the Divided D-23 formula was that it’s not really a divided formula at all (it’s D-23 with an alkaline after-bath)." In Schaefer's Book 2, AA does seem to differentiate between divided and two-solution methods of development. The process being talked about here seems more in the way of the "two-solution" process.

Yes, many of the developer called divided have a certain amount of developing going on in bath A so I think agitation in A is much more important than B for good results. Still, I would want to agitate the same way every time in bath A for consistent results just as you would using a single or one-shot developer. Same for bath B also.

John Wiegerink · Jan 14, 2025

Whoops! Milpool hit "post reply" slightly before I did. Sorry

retina_restoration · Jan 14, 2025

Chuck_P said:
That' interesting, I'm doing similar minimal agitation in bath B but haven't considered not agitating in bath A, and I will take your word for it. If you look at the article I linked to, the author suggests that it's not "really" a divided developer as he states: "My first thought when seeing the Divided D-23 formula was that it’s not really a divided formula at all (it’s D-23 with an alkaline after-bath)." In Schaefer's Book 2, AA does seem to differentiate between divided and two-solution methods of development. The process being talked about here seems more in the way of the "two-solution" process.

It's true - the Bath A in Divided D-23 (and Thornton 2 Bath) is a functional developer by itself. But of course, at 4 or 5 minutes, not a lot has happened yet in Bath A. It's when the developing agent (In this case Metol) comes in contact with the alkali, there's a significant increase in activity. The only difference between standalone D-23 and Divided D-23 is that the standalone D-23 has one gram more Metol and 20 grams more sulfite. It's enough to make a difference, but it's not that big a difference.

If you were inclined to experiment, you could easily prove how functional Bath A is on its own by leaving film in it for 12-15 minutes, followed by stop and fix. (No Alkali bath) That said, there is a difference in effect when using the Divided D-23 recipe: avoiding overdevelopment of high values, while preserving the tonal separation of the lower values. D-23 as a standalone developer doesn't have the same ability.

Chuck_P · Jan 14, 2025

retina_restoration said:
If you were inclined to experiment, you could easily prove how functional Bath A is on its own by leaving film in it for 12-15 minutes, followed by stop and fix. (No Alkali bath) That said, there is a difference in effect when using the Divided D-23 recipe: avoiding overdevelopment of high values, while preserving the tonal separation of the lower values. D-23 as a standalone developer doesn't have the same ability.

I don't doubt the functionality of it on it's own as a standalone developer. But I am certainly experimenting with time and agitation schemes.

Chuck_P · Jan 14, 2025

Chuck_P said:
The process being talked about here seems more in the way of the "two-solution" process.

I was reviewing the thread from the beginning and saw where @Milpool had made this very point fairly early in the thread.

gorbas · Jan 15, 2025

retina_restoration said:
If you were inclined to experiment, you could easily prove how functional Bath A is on its own by leaving film in it for 12-15 minutes, followed by stop and fix. (No Alkali bath)

If I can suggest, anybody who is interesting in this kind of developer should test bath A for 4 or 6 minute (or for whatever time), just to be aware how much development happens in that time. When I did that test it produced underdeveloped negative that was fine enough to be printed on grade #4 or 5.
12-15min will give you full development with most of the films.
Also, what is wrong with "normal" agitation in bath B? You are not going to wash out absorbed bath A in film with bath B. I always used the same agitation in both baths.
No issues at all.

John Wiegerink · Jan 15, 2025

Sorry if this sounds a little off topic, but while we are talking about first development times I thought this might be of interest. Years back I tried a two bath method of compensation that I had read about in one of Adams books and a couple other places. I was having a hard time with burnt out highlights. I later found out I was always way overexposing, which compounded the problem. Before I found this out I tried D23 and later ID11 with just a second bath of H2O. You had to shorten your development times in bath A to just under full development and then pull your film and set it gently in the water bath. I don't remember that the time in water was critical or not, but you didn't want to do any agitation or disturb the film in anyway in the water bath. That helped my negatives a lot, but didn't cure my problem altogether. Being a newbie to B&W film processing and enlarging I had read that it was always good to down rate the manufactures ASA rating. Will, if a little is good, then a whole lot is better, right. It wasn't until I learned that what I was doing was compounding my problem that my problem was cured. Still, this lesson taught me something about compensating development and how it works.

retina_restoration · Jan 15, 2025

Chuck_P said:
I don't doubt the functionality of it on it's own as a standalone developer. But I am certainly experimenting with time and agitation schemes.

Yes, I realize that - I was just relating my personal experience in regard to the activity of Bath A

gorbas · Jan 15, 2025

John Wiegerink said:
You had to shorten your development times in bath A to just under full development and then pull your film and set it gently in the water bath. I don't remember that the time in water was critical or not, but you didn't want to do any agitation or disturb the film in anyway in the water bath. That helped my negatives a lot, but didn't cure my problem altogether.

I'm doing 3 minutes water bath after Rodinal 1:50 and I still do it with regular agitation. This one is super hard to prove what is right, one way or another.

John Wiegerink · Jan 15, 2025

gorbas said:
I'm doing 3 minutes water bath after Rodinal 1:50 and I still do it with regular agitation. This one is super hard to prove what is right, one way or another.

Yup, I can't say one way or the other as to which way to go on the bath B agitation. I'm just going by what I've read so far. My thought was that minimal agitation in bath B and fairly light/normal agitation in bath A might lead to a little more apparent sharpness/crispness due to slight edge effects. Don't know for sure, but it seems to work fairly well that way and the negatives print with ease for wet printing.
I should say that this is what I do for BTTB and not the single bath B H2O one.

gorbas · Jan 15, 2025

I'm under impression that for real edge effect you need much more time, 4 or 5 min it's just too short, but again it has to be tested.

Alan Johnson · Jan 15, 2025

Attached the main quote about BTTB from the earlier book "Elements" by Barry Thornton.
BTTB was just one of many developers he discussed in this book. He was very particular about exposure (spot meter) and his belief that the negative had to be just right to provide a fine print. This gives an early version of the formula which he later modified (post 209).

retina_restoration · Jan 15, 2025

gorbas said:
I'm doing 3 minutes water bath after Rodinal 1:50 and I still do it with regular agitation. This one is super hard to prove what is right, one way or another.

I don't think it is. If I were looking to "prove" anything about this technique, I would expose a section of film with the exact same subject (maybe a bit of bracketing) and cut it in two, developing one half with and one half without the water bath. That way you'd have clear evidence one way or the other.

gorbas · Jan 15, 2025

retina_restoration said:
I don't think it is. If I were looking to "prove" anything about this technique, I would expose a section of film with the exact same subject (maybe a bit of bracketing) and cut it in two, developing one half with and one half without the water bath. That way you'd have clear evidence one way or the other.

Sorry Paul, I was talking about effects of minimal or regular agitation in water bath or earlier in B bath. On my negatives developed in Rodinal I can clearly see benefits of after water bath. It's my habit to process short strips of film (3-5 frames) to see what is going on. As somebody who has been bitten by "snakes" of under agitation I will stay away from any sort of "minimal" agitation with any developer.

Barry Thornton's two-bath question about time and temperature

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