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

[Igor_77]

I've got rather strange results with HP5+ and Delta 400 35 mm and 120 films using homemade BTTB. Time 5+5 min, T=20C. Agitation was standart.
Too mach fog and contrast, films look like overdeveloped.
One film developed in Pyrocat HD has mach less fog and less contrast.

 

[Romanko]

Too much fog and contrast, films look like overdeveloped.

This is very unusual. BTTB is more likely to give low-density/low-contrast negatives.

Did you shoot your films at the box speed of ISO 400?
Are you sure they are overdeveloped and not overexposed?
What formulae did you use?
Were the solutions fresh or reused?

The recommended agitation is
Bath A - 30 seconds initial, then 10 seconds at each minute;
Bath B - 5 seconds initial, then 5 seconds at each minute.
I doubt that more rigorous agitation would result in very high contrast, though.

Contaminating part A with part B could turn BTTB into a high-contrast developer.

I used BTTB a lot and never had that problem. I had a few underdeveloped negatives and uneven development but I blame my technique. BTTB is an excellent developer and I suggest you give it another chance.

 

[Igor_77]

This is very unusual. BTTB is more likely to give low-density/low-contrast negatives.

Did you shoot your films at the box speed of ISO 400?
Are you sure they are overdeveloped and not overexposed?
What formulae did you use?
Were the solutions fresh or reused?

The recommended agitation is
Bath A - 30 seconds initial, then 10 seconds at each minute;
Bath B - 5 seconds initial, then 5 seconds at each minute.
I doubt that more rigorous agitation would result in very high contrast, though.

Contaminating part A with part B could turn BTTB into a high-contrast developer.

I used BTTB a lot and never had that problem. I had a few underdeveloped negatives and uneven development but I blame my technique. BTTB is an excellent developer and I suggest you give it another chance.

Fresh solution for the first time and from the shelf one month later.
Agitation was as described.
I shoot HP5+ at ISO 250.
Films look overdeveloped in very active developer. The difference between shadows and highlights ist very big.

 

[Romanko]

The difference between shadows and highlights is very big.

To me that sounds like over-development.
In my experience EI 250 is a good choice for HP5+.

Is this the formula that you used?

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

Bath B
Sodium Metaborate 12g
Water to 1 litre

John Finch (@Pictorial Planet) suggests you can increase the concentration of Bath B for higher contrast. I tried it and it works but the effect is subtle. It won't give you massively overcooked negatives.

There is no pre-wash (and even if you used one it won't increase contrast).

Interesting. I ran out of ideas apart from remixing your solutions and trying again on a short strip of 35 mm film. Maybe try a piece of fresh unexposed film to check fog levels.

 

[Milpool]

Fresh solution for the first time and from the shelf one month later.
Agitation was as described.
I shoot HP5+ at ISO 250.
Films look overdeveloped in very active developer. The difference between shadows and highlights ist very big.

Developing time in bath A determines contrast.

It is also best not to re-use bath B although whether or not this affects anything materially would be variable.

 

[Alex Benjamin]

I shoot HP5+ at ISO 250.
Films look overdeveloped in very active developer. The difference between shadows and highlights ist very big.

I had the same experience with HP5+ @ 250 in TTB.

I've lowered my time to 4:30 minutes instead of 5:00, which helped. Contrast is still well defined, but the highlights aren't burned, and the negs are a joy to print, especially with split grade. I will soon try some at 4:00 minutes, just to see if contrast is even more balanced.

Strangely enough, I've had the opposite effect with Tri-X, where 5:00 minutes did not seem quite enough time to me. But it might be that I'm just used to seeing the higher-contrast HP5+ negs.

You have to remember that Barry Thornton was obsessed with sharpness, and that this developer was conceived to deliver full brightness range without burning the highlights, and giving full detail in the shadows. It's possible your negs are slightly overcooked, but an appearance of a big difference between shadows and highlights is also partly a result of sharpness. As long as your highlights aren't burned, you should be fine.

If your negs are indeed over-developed, might be because of over-agitation in bath B.

The recommended agitation is
Bath A - 30 seconds initial, then 10 seconds at each minute;
Bath B - 5 seconds initial, then 5 seconds at each minute.
I doubt that more rigorous agitation would result in very high contrast, though.

That's not Barry Thornton's recommendation.

I only shoot 120 and follow Thornton's instructions for the second bath, i.e., after three very strong taps of the tank to dislodge air bubbles, no agitation for the first three minutes. I follow that with two inversions at minute 3 and minute 4.

Thornton states that this agitation pattern should not be followed for 35mm, but remains vague as to what should be.

Here's the relevant excerpt :

The technique is the same for all versions of the two bath. Bath A contains only the developing agents and preservative and sometimes a restrainer. Bath B contains the accelerator, and sometimes a restrainer. The film is developed in Bath A with agitation every half or full minute -its not critical. Actually little development takes place. Mostly the film is becoming saturated with the developing solution.

However, some development does take place and agitation is important to prevent streaking. The solution is then poured off and saved. Drain the tank well but don't rinse or use a stop bath. Then pour in Bath B, and after a quick rap of the tank on a hard surface to dislodge any air bells, let the tank stand still with no agitation for three minutes or so when all development has ceased. Note, though, that while no agitation is ideal, and usually works well for unsprocketed roll film (120/220), there can be streamers from 35mm sprocket holes. This seems to vary with different kinds of tanks, different films, and the local water characteristics. Do your own experiments to determine the minimum agitation you can achieve without streaking before committing a crucial film to the process. Perhaps try one minute intervals to start with.

In the second bath the developer soaked into the film emulsion is activated by the accelerator. In the highlight regions where the developed silver will be densest, the developer available in the emulsion is soon exhausted and development halts, thus automatically limiting the density of the negative at that point.

 

[Igor_77]

To me that sounds like over-development.
In my experience EI 250 is a good choice for HP5+.

Is this the formula that you used?

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

Bath B
Sodium Metaborate 12g
Water to 1 litre

John Finch (@Pictorial Planet) suggests you can increase the concentration of Bath B for higher contrast. I tried it and it works but the effect is subtle. It won't give you massively overcooked negatives.

There is no pre-wash (and even if you used one it won't increase contrast).

Interesting. I ran out of ideas apart from remixing your solutions and trying again on a short strip of 35 mm film. Maybe try a piece of fresh unexposed film to check fog levels.

Yes, this one. I plan to remix both solution and retry.

 

[Igor_77]

I had the same experience with HP5+ @ 250 in TTB.

I've lowered my time to 4:30 minutes instead of 5:00, which helped. Contrast is still well defined, but the highlights aren't burned, and the negs are a joy to print, especially with split grade. I will soon try some at 4:00 minutes, just to see if contrast is even more balanced.

Strangely enough, I've had the opposite effect with Tri-X, where 5:00 minutes did not seem quite enough time to me. But it might be that I'm just used to seeing the higher-contrast HP5+ negs.

You have to remember that Barry Thornton was obsessed with sharpness, and that this developer was conceived to deliver full brightness range without burning the highlights, and giving full detail in the shadows. It's possible your negs are slightly overcooked, but an appearance of a big difference between shadows and highlights is also partly a result of sharpness. As long as your highlights aren't burned, you should be fine.

If your negs are indeed over-developed, might be because of over-agitation in bath B.



That's not Barry Thornton's recommendation.

I only shoot 120 and follow Thornton's instructions for the second bath, i.e., after three very strong taps of the tank to dislodge air bubbles, no agitation for the first three minutes. I follow that with two inversions at minute 3 and minute 4.

Thornton states that this agitation pattern should not be followed for 35mm, but remains vague as to what should be.

Here's the relevant excerpt :

The technique is the same for all versions of the two bath. Bath A contains only the developing agents and preservative and sometimes a restrainer. Bath B contains the accelerator, and sometimes a restrainer. The film is developed in Bath A with agitation every half or full minute -its not critical. Actually little development takes place. Mostly the film is becoming saturated with the developing solution.

However, some development does take place and agitation is important to prevent streaking. The solution is then poured off and saved. Drain the tank well but don't rinse or use a stop bath. Then pour in Bath B, and after a quick rap of the tank on a hard surface to dislodge any air bells, let the tank stand still with no agitation for three minutes or so when all development has ceased. Note, though, that while no agitation is ideal, and usually works well for unsprocketed roll film (120/220), there can be streamers from 35mm sprocket holes. This seems to vary with different kinds of tanks, different films, and the local water characteristics. Do your own experiments to determine the minimum agitation you can achieve without streaking before committing a crucial film to the process. Perhaps try one minute intervals to start with.

In the second bath the developer soaked into the film emulsion is activated by the accelerator. In the highlight regions where the developed silver will be densest, the developer available in the emulsion is soon exhausted and development halts, thus automatically limiting the density of the negative at that point.

Thanks a lot Alex,
I'll try to reduce agitation in second bath with old solutions, then will mix new ones.

 

[What About Bob]

When I first started out using BT2B I would reuse Bath B for about three or four times then dispose of it. I now mix Bath B for use as a one-shot solution, as I go. It is consistent, metaborate is cheap and it is one less chemical to store too. I will kind of miss the cool lemonade looking colors of Bath B.

My tank volume was worked out to be 660ml. The AP tank requires a bit more volume than what is stated on the bottom of the tank. 660 is a little extra and ensures good coverage and the number works out mathematically for me when measuring out chemicals.

For the 7, 12, and 20 grams per liter values of metaborate; when breaking the 1 liter volume down to 660ml this will come down to 4.6, 7.9 and 13.2 grams of metaborate, respectively. Right when I am about to develop I get the gram scale out and measure out the metaborate for one time use.

@Alex Benjamin: I ordered five roll of Tri-X the other night and will be putting it through BT2B. I haven't used Tri-X in ages and am looking forward to it. I loved the 320 version of it.

 

[Alex Benjamin]

I ordered five roll of Tri-X the other night and will be putting it through BT2B. I haven't used Tri-X in ages and am looking forward to it.

Let us know how they come out. As I said, for some reason, I haven't been able to find a sweet spot for Tri-X in TTB, but neither have I for the same film in D-23 (very similar to TTB in many ways).

I now mix Bath B for use as a one-shot solution, as I go. It is consistent, metaborate is cheap and it is one less chemical to store too.

Thornton says both Bath A & Bath B should be good for about 15 films per litre. I aim for caution and go with 12 120 films. Haven't seen any difference between film #1 and film #12.

That said, the fact that Bath B can be mixed at room temperature makes it tempting to go one-shot with it.

 

[Igor_77]

I've done some experiments. First I developed Delta 400 10.24 film 5 min/20C only in first bath - slightly visible image traces and a lot of fog comparing to fixed/undeveloped film. Then I developed 3 pieces of another films (APX100 11.2020, HP510.24, Delta100 05.25) and the rest of Delta 400 10.24. All films except Delta 400 10.24 have a very little fog and awaiting contrast, so I think this rolls of Delta 400 10.24 were kept somewhere in bad circumstances.
Now I plan remix BTTB and take some test photos/

 

[retina_restoration]

I've done some experiments. First I developed Delta 400 10.24 film 5 min/20C only in first bath - slightly visible image traces and a lot of fog comparing to fixed/undeveloped film. Then I developed 3 pieces of another films (APX100 11.2020, HP510.24, Delta100 05.25) and the rest of Delta 400 10.24. All films except Delta 400 10.24 have a very little fog and awaiting contrast, so I think this rolls of Delta 400 10.24 were kept somewhere in bad circumstances.
Now I plan remix BTTB and take some test photos/

In my own use of Delta 400, it has one of the lowest base + fog levels of all films I have used, so I suspect you're right - the film was stored incorrectly, resulting in excessive fog.

 

[Igor_77]

In my own use of Delta 400, it has one of the lowest base + fog levels of all films I have used, so I suspect you're right - the film was stored incorrectly, resulting in excessive fog.

Too long way from production to consumer-((

 

[BHuij]

@Igor_77 it sounds like you've solved this - Delta 400 might just be fogged from age or heat or something. But I was going to suggest that maybe if you're mixing Bath A in tap water that your tap water is too alkaline, and acting somewhat as an accelerator. If you're getting good results with other films though, then I'm probably wrong about that hypothesis.

Very timely for me to find this thread. I just read Edge of Darkness and got very curious about BTTB. I've been using Mytol with Delta 100 and HP5+, and while I've been pretty happy with it in 35mm up to 8x10 print sizes, I did an 11x14 print the other day from a 35mm Delta 100 negative in Mytol. There was essentially no grain, but I was slightly unhappy with the overall sharpness. I don't think my taking lens or some other technique issues is to blame. Thornton posits that XTOL (and Mytol is, essentially XTOL) produces very fine-grain, but isn't particularly "high definition" by his own definition of that quality (which basically seems to boil down to having low but not no grain, extremely high acutance, and preferably edge effects).

Got curious enough to order some Metol and Sodium Metaborate and side by side BTTB against XTOL using HP5+, FP4+, and Delta 100 to see if I happen to like it better.

After reading through this thread, I'm inclined to use Bath B one-shot. One less variable to worry about that may or may not affect consistency from roll to roll. One question I have - Thornton claims 15 films from a liter each of A and B. While B getting exhausted or overly contaminated by carryover makes sense, I don't know if I understand why Bath A would need to be replaced after 15 films. If I'm understanding correctly, it doesn't "exhaust." It just loses a bit of volume every time you use it. Why then could I not use it until it will no longer cover the film in my developing tank?

 

[Igor_77]

Just developed another HP5+ in new mix of BTTB, everything is OK. Film was shot as ISO200, 5+5 20C, looks a little bit overexposed. A little bit of previous Delta 400 (used as indikator) developed together as a test is very foggy. The cause was film.

 

[MattKing]

While B getting exhausted or overly contaminated by carryover makes sense, I don't know if I understand why Bath A would need to be replaced after 15 films. If I'm understanding correctly, it doesn't "exhaust." It just loses a bit of volume every time you use it. Why then could I not use it until it will no longer cover the film in my developing tank?

Perhaps due to "development" byproduct "contamination" coming from the films?

 

[BHuij]

Makes sense from my layman's perspective, I suppose.

 

[Milpool]

If I'm understanding correctly, it doesn't "exhaust." It just loses a bit of volume every time you use it. Why then could I not use it until it will no longer cover the film in my developing tank?

Part A is developing film while it is in the tank, so it is both gradually exhausting, and building up development reaction products.

There are two basic types of divided development. (1) Solution A is inactive due to it having a neutral or mildly acidic pH, and whatever is absorbed/carried over is activated by the solution B alkali. (2) Solution A is a fully functioning developer, but development time in solution A is truncated, and whatever is absorbed/carried over keeps developing in the alkaline environment of solution B until exhausted.

Though both types are ultimately self-limiting when the film is in part B, the second type can give any desired gradient by varying the amount of development in part A.

This Barry Thornton process is the second type. Part A is a complete developer - basically D-23. Actually this process is only trivially different than the old Adams divided D-23 or even Stoeckler.

 

[Romanko]

If I'm understanding correctly, it doesn't "exhaust."

It oxidizes and builds up development byproducts (bromides) that act as restrainers. I reused BTTB for several rolls and subjectively the negatives were fine.

I develop HP5+ in D23 1+1 and I am very happy with the results. I expect BTTB to be very similar.

John Finch mentions in his book that you can control contrast by modifying the concentration of bath B.

 

[Igor_77]

@Igor_77 it sounds like you've solved this - Delta 400 might just be fogged from age or heat or something. But I was going to suggest that maybe if you're mixing Bath A in tap water that your tap water is too alkaline, and acting somewhat as an accelerator. If you're getting good results with other films though, then I'm probably wrong about that hypothesis.

I use deionized or sometimes boiled water only for film developing process.

 

[retina_restoration]

It oxidizes and builds up development byproducts (bromides) that act as restrainers. I reused BTTB for several rolls and subjectively the negatives were fine.

I develop HP5+ in D23 1+1 and I am very happy with the results. I expect BTTB to be very similar.

John Finch mentions in his book that you can control contrast by modifying the concentration of bath B.

John Finch says a lot of things, many of which I believe should be taken with a pinch of sodium chloride.

 

[BHuij]

John Finch says a lot of things, many of which I believe should be taken with a pinch of sodium chloride.

In this case, he appears to just be re-stating something Thornton himself talks about - that you can increase contrast by using 20g of sodium metaborate instead of 12g in bath B, and you can decrease contrast by using 7g instead of 12g.

 

[Milpool]

In this case, he appears to just be re-stating something Thornton himself talks about - that you can increase contrast by using 20g of sodium metaborate instead of 12g in bath B, and you can decrease contrast by using 7g instead of 12g.

That doesn’t really do much of anything in my experience. In fact I found 5g/l borax was enough to do the same thing as the traditional 10g metaborate, and even going to sodium carbonate didn’t change contrast (although it increased fog). I didn’t make any attempt at evaluating relative graininess but at least from a sensitometry perspective I found altering bath B is generally ineffective for contrast control. The real control is simply lengthening/shortening the development time in bath A.

 

[BHuij]

Interesting. When differences in experience on something this simple arise, I always wonder why. Did Thornton actually see a contrast increase when he used 20g of metaborate instead of 12g for Part B of his developer? If so, why were you unable to replicate his results? If not, what did he stand to gain by making such a claim? Very strange.

As usual, enough conflicting opinions here that I'll probably just test it myself and come to my own conclusions

 

[Igor_77]

I've seen these graphs somewhere already..