Advice on my Two Bath Developer

[cliveh]

Can someone please explain to me why you would want to use 2 bath development? What enhancement does this give to the image?

 

[relistan]

Looks good, relistan. It’s fun learning about these things and making something that does what you want is a nice bonus.

Thanks, and the advice and support are appreciated. I was just looking very carefully at the scan of that image and realized there is a noticeable edge effect happening. Take a look at where the edge of the tower crosses the landscape. The area by the sky (upper half of this crop) appears to have a noticeable edge effect happening unless I'm misreading this. The line continues below the tree line, but with a much less noticeable edge.

I may have to rescan to make sure it's not the scanner. Better yet, stick on the enlarger.

 

[relistan]

Can someone please explain to me why you would want to use 2 bath development? What enhancement does this give to the image?

It's discussed through most of the thread above.

Essentially it's about control of contrast, ease of use, re-usability, etc. It's not magic, but it is nice when working well.

 

[cliveh]

It's discussed through most of the thread above.

Essentially it's about control of contrast, ease of use, re-usability, etc. It's not magic, but it is nice when working well.

I thought control of contrast was about correct exposure for the original lighting contrast in the scene, followed by correct time/temperature of development of the negative, followed by correct contrast in printing? Where does two bath development fit in?

 

[Alan Johnson]

In the first bath the emulsion absorbs the same amount of developer in all areas. In the second bath the more exposed areas quickly use up this developer without much increase in density. The less exposed areas, shadows, use up the developer more slowly and the increase in density is proportionately more. So the contrast is reduced and the effective film speed may be increased.

 

[cliveh]

In the first bath the emulsion absorbs the same amount of developer in all areas. In the second bath the more exposed areas quickly use up this developer without much increase in density. The less exposed areas, shadows, use up the developer more slowly and the increase in density is proportionately more. So the contrast is reduced and the effective film speed may be increased.

I understand why the contrast is reduced, but not why the effective film speed is increased. Can you please elaborate?

 

[relistan]

Sorry @cliveh I replied from my phone last night. In the photo from France I posted above, that was intense summer light with a huge differential between the sunlit and shadowy areas. The two bath has given a much more controlled contrast across the frame. You can see how, given one less stop of exposure, I would have increased the contrast because most of the difference would be in the shadows, given what Alan and Michael described above. But even one more stop, giving EI200 on this film, would be a good, very printable exposure. You can, within the limits of reason, adjust frame by frame on roll film. But because 2B-1 is more of a divided developer, time in the first bath has an effect. This is one reason why @michael_r was suggesting to try to get the pH down more. Which I will experiment with further.

 

[Donald Qualls]

Can someone please explain to me why you would want to use 2 bath development? What enhancement does this give to the image?

Aside from other qualities mentioned above, two-bath developers in general have little if any compensation needed for temperature (as long as you're above about 65F/17C you're good) and no great precision in timing (because the first bath needs a minimum time to soak into the emulsion, but produces little or no development, while the second bath develops to exhaustion of the carried-over first solution).

 

[relistan]

Here's a little update on this developer. The first batch is still working well, just developed some films this weekend. Here's a sample from two weeks ago, on ADOX HR-50, a high contrast film, intentionally shot with high contrast and backlighting to push the developer kind of hard. This was developed 6 mins A, 4 mins B @ 20C. I'm quite happy with the results. I think I would shoot it at EI25 or 32 next time.

I have developed a way of getting very close to a correct dev time for new films using a two bath. I test a leader clip at 4 mins, then 5, longer if needed and then always 4 mins in B. When the A time is enough to produce the deepest black it will give, that's the time I use. I don't have a densitometer so I have a light that I know I should only be able to see the filament through. If I can see the edge of the bulb it needs more time. The compensating effect takes care of getting the mid tones and highlights on track. It takes 15-25 minutes or so to get a time that will work and then I just plonk the roll in and go.

I got a decent pH meter this weekend and on Saturday I will calibrate it and get a reading to see what the actual pH instead of just from the paper strips.

 

[pentaxuser]

Relistan have you discovered where the edge effect you mentioned comes from? The cat is saying "I hope this portrait gives me that high contrast noirish look. I have always wanted to catch a "Maltese Falcon"

So for goodness sake do not show the cat this portrait with its fine detail and full tones

pentaxuser

 

[relistan]

Relistan have you discovered where the edge effect you mentioned comes from? The cat is saying "I hope this portrait gives me that high contrast noirish look. I have always wanted to catch a "Maltese Falcon"

So for goodness sake do not show the cat this portrait with its fine detail and full tones

pentaxuser

HAHA, indeed, that would be a terrible mistake!

Regarding edge effect: I inspected the negatives with a loupe and it looks to me like there is an edge effect from the developer, but it was accentuated noticeably by sharpening in the scan. The negatives look OK. I have, however, increased agitation in the second bath to 1 inversion a minute, with 2 at the beginning. This seems to have reduced it to normal levels while still fully developing the negative. The cat photo was developed in this way and everything looks good.

 

[mohmad khatab]

Hello brother.
The Indian colleague (Raghu) once sent me a very simple recipe, for a simple developer like any regular developer (in fact I used AGFA12 at the time) but I think he will work for any developer (1 Bath)

And this developer has an assistant ,,
The developer works and after you finish it and return it to his bottle. But do not wash the film with water. You add the "Detail Highlight Solution", and this solution is very simple
0.35 g sodium hydroxide
0.70 borax
Half a liter of water.
At 20 ° C for 4 minutes, for medium-speed films up to 400 ISO, and for films higher than that, it is 5 minutes.
This solution is used for single clamping and is discarded.
In fact, I tried this idea and got very great results, but I could not get these pictures now because they are on another hard disk that I cannot access.
Greetings to you .

 

[relistan]

Hello brother.
The Indian colleague (Raghu) once sent me a very simple recipe, for a simple developer like any regular developer (in fact I used AGFA12 at the time) but I think he will work for any developer (1 Bath)

And this developer has an assistant ,,
The developer works and after you finish it and return it to his bottle. But do not wash the film with water. You add the "Detail Highlight Solution", and this solution is very simple
0.35 g sodium hydroxide
0.70 borax
Half a liter of water.
At 20 ° C for 4 minutes, for medium-speed films up to 400 ISO, and for films higher than that, it is 5 minutes.
This solution is used for single clamping and is discarded.
In fact, I tried this idea and got very great results, but I could not get these pictures now because they are on another hard disk that I cannot access.
Greetings to you .

Hi Mohmad, thank you. Yes, this is interesting: it's an alkaline second bath to allow for compensating development. That is a very small amount of chemistry. I'd be interested in the effect of this versus a water bath. Since you can't access your drive, maybe @Raghu Kuvempunagar has examples?

 

[Raghu Kuvempunagar]

I'd be interested in the effect of this versus a water bath. Since you can't access your drive, maybe @Raghu Kuvempunagar has examples?

Please ignore what he wrote. I gave him that suggestion in a specific context, but he generalized it and seems to be happy with his results. Won't blame him as he relies completely on machine translation.

 

[Donald Qualls]

This is the second kind of divided developers -- those that develop in the first bath, but continue to develop with carried-over chemistry in the second. Doing this with an existing developer like D-76 ought to give a strongly compensating effect, because developer in the highlights will exhaust quickly, but that in the shadows will not -- BUT this will be applied "on top of" the normal development that occurs in the first bath. This should bring up overall contrast a bit, but if left to run long enough will then bring up the shadows and lower the gamma or CI a little.

 

[mohmad khatab]

Hi Mohmad, thank you. Yes, this is interesting: it's an alkaline second bath to allow for compensating development. That is a very small amount of chemistry. I'd be interested in the effect of this versus a water bath. Since you can't access your drive, maybe @Raghu Kuvempunagar has examples?

Regarding the results of using a solution (highlighting details) ,, I found three pictures, but there are two problems,
These images were for (Delta) movie and it has been developed into a Buztiv movie, and not only that, it has been toned into brown using thiourea.
Therefore, this film was developed with 3 developers and 2 bleachers - and not only that, but a "detail highlighting solution" was used after a first developer and a second developer.
- Unfortunately, we did not have a scanner at that time, so one of the young men placed the chip in front of a laptop and took pictures on the mobile, so the judgment on the quality of the images will not be fair.
- Summary of the story: The size of the images is large, and the forum did not accept uploading these pictures, and I do not know how to send them to you ,, the minimum is 2.2 MB,

 

[gorbas]

To continue discussion on Two bath developers, in my post #20 in https://www.photrio.com/forum/threads/developer-for-aviphot-pan-200.182434/
I will repite recipe here:
"Baumann Diafine" (Origin of the formula is as murky as it can be, for something I could find in 1985)
A
Metol-3g
Potassium metabisulfite-30g
Hydroquinone-7.5g
Sodium Carbonate 1.3g
KBr-2g
Water to 1L
B
Sodium Carbonate-100g
Sodium Sulphite-10g
KBr-2g
Water to 1L

Interesting things that Bath A does not contain any Sodium sulphite but Potassium metabisulfite. I don't remember having any issues with keeping this developer active for months.
Then recently I found this reference in The film developing cookbook, 2nd edition, 2020.
"When carbonate is added to the working solution, the bisulfite (preferably sodium) is immediately broken down into sulfite and bicarbonate, producing a useful buffering effect.
My chemistry knowledge is close to 0, any comments about this from more knowledgeable chemist?

 

[relistan]

Interesting things that Bath A does not contain any Sodium sulphite but Potassium metabisulfite. I don't remember having any issues with keeping this developer active for months.
Then recently I found this reference in The film developing cookbook, 2nd edition, 2020.
"When carbonate is added to the working solution, the bisulfite (preferably sodium) is immediately broken down into sulfite and bicarbonate, producing a useful buffering effect.
My chemistry knowledge is close to 0, any comments about this from more knowledgeable chemist?

I would not describe myself as a knowledgeable chemist, but metabisulfite is an effective preservative for many developing agents, a silver solvent, and often used to lower the pH of a developer. 1.3g of carbonate will give you a reasonably high pH, and then the metabisulfite should bring it way back down. I would _guess_ from looking at those numbers that this is somewhat acidic, below pH 7. So that first bath should not develop really at all, despite the large amount of hydroquinone and metol.

A "buffer" in chemical terms (again, I am not an expert) is usually a combination of a base and and acid in such an arrangement that the pH is pretty stable and resistant to change with the addition of either more acid or more alkali.

Interestingly, looking at this formula, this is *very* close I would say to what I came up with for 2B-1 with regard to bath A. As far as I know, phenidone is usually substituted with metol at a ratio of about 1 to 10. So my 0.25g of phenidone is similar in activity to 2.5g of metol. I am using 8g of hydroquinone, again pretty close to your 7.5g. I am also using 35g of sodium sulfite. I believe the main difference is that 2B-1's bath A has an alkaline pH and so it can develop some in bath A. I am also using 1g of KBr instead of your 2.

The bath B is quite different from mine. Maybe someone else can comment, but that bath B seems to have a *lot* of carbonate.

 

[relistan]

I should have said: sulfite and metabisulfite preserve things by scavenging oxygen. I think that the sulfur dioxide gas given off by metabisulfite also acts as a preservative layer in the storage container as well if I remember correctly. Someone correct me if that's wrong.

 

[gorbas]

Thank you for the comment Relistan!
Yes, I agree, 100g of Carbonate in B is way overkill. On the end, we are limited with amount of A soaked in emulsion and on the film. Lower amount of carbonate will also lower need for restrainer - KBr. You probably seen in TFDC Haist's advice "If you need bromide then your alkalinity is to high".
Have great light!

 

[Raghu Kuvempunagar]

Thank you for the comment Relistan!
Yes, I agree, 100g of Carbonate in B is way overkill. On the end, we are limited with amount of A soaked in emulsion and on the film.

Part B was probably intended to be reused like Part A. If that's indeed the case then such high amount of carbonate does make Part B highly resistant to pH changes caused by the diffusion of Part A and development biproducts (usually acidic) into Part B over repeated use.

 

[Raghu Kuvempunagar]

Interesting things that Bath A does not contain any Sodium sulphite but Potassium metabisulfite. I don't remember having any issues with keeping this developer active for months.
Then recently I found this reference in The film developing cookbook, 2nd edition, 2020.
"When carbonate is added to the working solution, the bisulfite (preferably sodium) is immediately broken down into sulfite and bicarbonate, producing a useful buffering effect.

A roll of film absorbs at most 20ml of Part A. This means the entire roll has 30*(20/1000) = 0.6g of Metabisulphite in it (contrast this with ~100g carbonate that's there in Part B). When the bisulphite ions in the film come in contact with the carbonate ions in Part B diffusing into the film, some bicarbonate ions are formed which form a buffer with the incoming carbonate ions. However, with time bicarbonate ions will progressively diffuse out whereas more and more carbonate ions will diffuse in. So, how good the buffering will be is questionable.

@alanrockwood or @GLS can perhaps throw some light.

 

[GLS]

A roll of film absorbs at most 20ml of Part A. This means the entire roll has 30*(20/1000) = 0.6g of Metabisulphite in it (contrast this with ~100g carbonate that's there in Part B). When the bisulphite ions in the film come in contact with the carbonate ions in Part B diffusing into the film, some bicarbonate ions are formed which form a buffer with the incoming carbonate ions. However, with time bicarbonate ions will progressively diffuse out whereas more and more carbonate ions will diffuse in. So, how good the buffering will be is questionable.

@alanrockwood or @GLS can perhaps throw some light.

Yes, because the ratio of carbonate to bicarbonate ions will be very high at equilibrium in the emulsion, the buffer capacity will be negligible I expect.

I suspect the quote from the developing cookbook that @gorbas mentioned was in the context of a single bath developer, not two bath. Do you have the exact page this is from? I have a copy of that book so I can check.

 

[gorbas]

Thank you Guys!
Yes, Raghu, bath B was reused. Hard to remember after all those years, but at least 10-20 rolls before I made another batch.
GLS, page 35, under Sodium and Potassium bisulfite
For me it was interesting now to notice lack of sulfite in bath A and presence of carbonate. Most likely activity of carbonate there is reduced by acidity of metabisulfite as mention by Relistan.
If i remember correctly, the only other time I saw metabisulfite in developer recipe where in article about making regular developers as 2 part for better keeping.

 

[Raghu Kuvempunagar]

For me it was interesting now to notice lack of sulfite in bath A

Sulphite is formed in situ along with bicarbonate ions when the film is taken from bath A to bath B due to the reaction between bisulphite ions and carbonate ions.