Avoiding bromide drag in two-bath developers

Don_ih · Apr 21, 2021

I thought I would try to make a 2-bath developer, with the second bath being just sodium carbonate in solution. It worked really well (not sure how long it would last, but it worked properly for a couple of weeks), with around 4 minutes first bath, 5 minutes second bath for every film I tried. The first bath was constant rotary agitation in a Jobo and the second bath, obviously, was no agitation at all. The result was bromide drag, however, and I'm wondering how that could be avoided.

The first bath contained 1g metol, 15g sodium sulfite, 4g hydroquinone, and 1g potassium bromide to make 500ml.
The second bath was 20g sodium carbonate (washing soda) to make 500ml.

The amounts were pretty much off the top of my head and I was going to adjust them, depending on the results. The results, however, are actually as good as I want them except for the bromide drag. My not knowing much chemistry doesn't help - should I have omitted the potassium bromide? I included it because some of the film I wanted to develop exhibits too much base fog when developed normally.

I thought about removing the pot. bromide and trying again but I expect it won't really fix the situation.

gorbas · Apr 21, 2021

There is absolutely no need to avoid agitation in bath B. That will solve your problem for sure.
Maybe you can use less soda, 20g per litre?
Also, I'm hoping to try Thornton's variant with soda soon.
Your A formula is very similar to Vestal's recipe, of course, nothing wrong with it.

Don_ih · Apr 21, 2021

gorbas said:
There is absolutely no need to avoid agitation in bath B.

I tried a couple of swirling agitations while the film was in bath B and the film development died. The exposure was all controlled, so I know there was nothing wrong there and a subsequent strip developed normally with no agitation. I think agitation effectively washes the developer off the film.

I'm quite pleased with it as a developer. The bromide drag only appears in certain instances. Example:

A genuine success of the developer was with a tri-x film pack from the late 50s that was exposed in the late fifties. It was part of a paper purchase and I thought it was unexposed but it had 10 exposures in it. The first ones I developed in d76 didn't fare that well. The ones I developed in this two-bath came out much better. Example:

Of course, the developer doesn't fix degraded emulsion.

Raghu Kuvempunagar · Apr 21, 2021

If you do a gentle inversion once every minute in your second bath, you should be fine. Developer won't wash off.

Don_ih · Apr 21, 2021

Raghu Kuvempunagar said:
If you do a gentle inversion once every minute in your second bath, you should be fine. Developer won't wash off.

When I agitated, I swirled the tank, which moved the bath B more at the outside of the tank than at the inside. The negative strip on the inner loops of the reel was considerably more dense than at the outside. Perhaps a longer bath B if it's agitated.

Diafine bath B works best if the film is undisturbed. Agitation makes the negatives thinner. Their instructions call for "very gentle" agitation in both baths.

Frankly, I don't think much developer gets absorbed into the emulsion. I think it's mostly just wetting the surface.

But it's worth testing. The next time I attempt it, I'll test it with agitation in bath B and without, using identical negative strips.

Kino · Apr 21, 2021

I wonder if you could supplement Bath B with a small amount of Bath A to compensate for less absorption of developer than older film emulsions?

relistan · Apr 21, 2021

Having spent a lot of time with two baths I can assure you it soaks in and that's where most of the action happens. You can prove it with a quick surface rinse.

Given the likely pH of your first bath, some development is happening in there. So agitation there will affect your development. This looks harsh enough that I suspect this is where the issue is. I don't think it's bromide drag.

As others said you should lightly agitate in B. But the other factor is that I find this type of drag is worse when the developer is weaker. You only get what's soaked in, so agitation can have more effect especially on a weak mixture. I consider that mixture a bit on the weak side for a two bath given all my own testing. Try doubling the metol and HQ, take it easy with agitation and I'd bet you don't see this again.

Edit: I should point out that at that strength you'd be pretty close to my 2B-1 developer in activity, but with less sulfite. https://imager.ie/a-phenidone-hydroquinone-two-bath-developer/

Don_ih · Apr 21, 2021

Kino said:
I wonder if you could supplement Bath B with a small amount of Bath A to compensate for less absorption of developer than older film emulsions?

I've reused the same batch of sodium carbonate solution 10 times or so, so it's been getting a bit of bath A mixed in with it as it goes on. Given that I didn't notice drag on my first strips, I think

relistan said:
this type of drag is worse when the developer is weaker

might be right. I'm getting good density - the same density after a dozen tests, actually - but the developing agents absolutely have to be wearing out. If I had glycin, I'd add that and increase the metol. My next mix, if I determined this mix didn't work, would have doubled the metol and bumped up the hydroquinone. So, maybe there are a few things to try before pouring what I have down the drain: agitate, no agitate, and both of those again with reduced sodium carbonate in bath B. Then mix a stronger batch of A and see what happens.

Don_ih · Apr 21, 2021

relistan said:
Edit: I should point out that at that strength you'd be pretty close to my 2B-1 developer in activity, but with less sulfite. https://imager.ie/a-phenidone-hydroquinone-two-bath-developer/

I was going to ask if it might be a good idea to add boric or citric acid to bath A to get the activity down - then I looked at your recipe.

Raghu Kuvempunagar · Apr 21, 2021

You can perhaps:
1. increase the concentration of your first bath to make it work well with gentle agitation in second bath.
2. not change the concentration but do two rounds of two bath development (with gentle agitation) along the lines of Rudiger Hartung.
3. switch to a time-tested two bath developer like Thornton's.

relistan · Apr 22, 2021

Don Heisz said:
I was going to ask if it might be a good idea to add boric or citric acid to bath A to get the activity down - then I looked at your recipe.

Most people would recommend sodium metabisulfite to bring the pH down. It has a further solvent effect though. I have citric acid, it's cheap, and it works fine. 1980s Diafine used it.

Don_ih · Apr 22, 2021

Raghu Kuvempunagar said:
switch to a time-tested two bath developer like Thornton's.

Now where's the fun in that? I have pretty much everything I need to make any regular MQ developer - this is just to gain a bit more insight than you can from following recipes - and feels a bit more creative.

relistan said:
I have citric acid

I know I have boric acid. I may have citric acid somewhere.

Raghu Kuvempunagar said:
increase the concentration of your first bath to make it work well with gentle agitation in second bath.

This seems to make sense, as was already said above. But increasing strength of bath A would suggest it would need an acid added to cut alkalinity, to keep bath A from becoming D23 with added hydroquinone.

Alan Johnson · Apr 22, 2021

Don,
Normally with 2-bath development in small tanks the width of the film rests in a vertical position.
Is that the case with your Jobo?
Much more is known about development in small tanks.

Don_ih · Apr 22, 2021

Alan Johnson said:
Don,
Normally with 2-bath development in small tanks the width of the film rests in a vertical position.
Is that the case with your Jobo?
Much more is known about development in small tanks.

The film was horizontal, being constantly rotated by the jobo for Bath A, but was standing vertical and motionless for Bath B.

Alan Johnson · Apr 22, 2021

https://www.photrio.com/forum/threads/developer-for-aviphot-pan-200.182434/
With my experiment in a small tank with 5 min in bath B I agitated bath B 2 inversions at start then 1 inversion at 2 min and another at 4 min, no sign of unevenness.
Recently I changed this to 4 1/2 min with 2 inversions at start and 1 inversion at 2 min, again no unevenness.
Since uneven results were found by swirling would it be practicable to try rapid inversion?

Raghu Kuvempunagar · Apr 22, 2021

Adding a few drops of Fotoflo to bath A might help.

Don_ih · Apr 22, 2021

Alan Johnson said:
https://www.photrio.com/forum/threads/developer-for-aviphot-pan-200.182434/
With my experiment in a small tank with 5 min in bath B I agitated bath B 2 inversions at start then 1 inversion at 2 min and another at 4 min, no sign of unevenness.
Recently I changed this to 4 1/2 min with 2 inversions at start and 1 inversion at 2 min, again no unevenness.
Since uneven results were found by swirling would it be practicable to try rapid inversion?

My swirling wasn't like a rotating agitator - it was me lightly swirling the tank. I need to test again with some agitation, in case something else was the problem during that test. That agitation was done specifically to stop bromide drag. It did that at the expense of density.

I looked at your thread. I expose Rollei Superpan 200 at around 160 and develop in d76 1:1 for 10 minutes, 45 second, then I let it soak in a borax solution for 5 minutes as a second bath.

Don_ih · Apr 22, 2021

Raghu Kuvempunagar said:
Adding a few drops of Fotoflo to bath A might help.

Interesting suggestion. What would it do, though?

ParkerSmithPhoto · Apr 22, 2021

When I was a Barry Thornton Two Bath user, I would pour in the B Bath, agitate five seconds, then leave it for two minutes, then agitate another five seconds, two more minutes and then stop bath. Never had a problem.

That being said, I've moved back to a single bath developer. Many of the claims that Thornton made are unsupported by testing. You still have to control time and temperature if you want to get consistent results, and the B bath is just a wild card thrown into the mix.

I got some great negs from BTTB and Diafine, it's just much easier and more consistent with a single bath developer.

Don_ih · Apr 22, 2021

ParkerSmithPhoto said:
it's just much easier and more consistent with a single bath developer

I totally agree with that. I was specifically hoping to reduce base fog from expired delta 400 (I have a bulk roll) - it does reduce it. Short development times and lower activity, plus the high concentration of potassium bromide, the film base is about as clear as it gets. Exposed and developed normally in d76, the frames can't even be distinguished by my scanner.

Other than that, though, this is just a learning experiment.

Raghu Kuvempunagar · Apr 22, 2021

Don Heisz said:
Interesting suggestion. What would it do, though?

See this suggestion by Sandy King.

"To avoid streaks and uneven development I advise adding a few drops of a wetting agent like PhotoFlo to Solution A as this promotes even draining of the solution."

Don_ih · Apr 22, 2021

Raghu Kuvempunagar said:
See this suggestion by Sandy King.

"To avoid streaks and uneven development I advise adding a few drops of a wetting agent like PhotoFlo to Solution A as this promotes even draining of the solution."

Streaks and uneven development aren't the problem, though. Funny thought to add PhotoFlo to developer. I remember reading in one of those old Kodak books that PhotoFlo should be kept out of developer. But lots of people add it to dev. At the very least, it doesn't seem to hurt.

Andrew O'Neill · Apr 22, 2021

When I do two-bath pyrocat-hd, I always agitate, rather vigorously at first, in the second bath. I also put a few drops of photo-flo in bath A. Agitation in bath A is gentle for about 5 seconds, every minute. I do exactly the same for divided D-23.

Don_ih · Apr 22, 2021

Well, I tested again but with continuous rotary agitation of Bath A and, for Bath B, several inversions at the start and 2 inversions every minute. So, I'm not sure what happened to make my previous negatives thin, since I was certain they were accurately exposed - perhaps I set the timer wrong for one of the baths? This time, no bromide drag.

This is a crop from a pretty blurry phone picture of the negative. 150 watts were shone on one side of the face, casting a shadow across white paper, so there is a good range of tones from black to white. No drag. You may notice two spots that didn't get fixed in the film edge. That's due to my loading film onto the reels emulsion facing out. That prevents any tiny bit of whatever that may get poured in with the developer from scratching the emulsion while the film is rotating in the Jobo. It quite possibly contributes to the bromide drag as well, since developer will bead up in there, trapped against the sprocket holes, and stays there if you don't agitate bath 2 - then kinda runs down the film, adding density as it goes. Or that's my guess.

Anyway, since this film, when developed in d76, has base fog roughly equivalent to what amounts to middle grey, I'm pleased.

Raghu Kuvempunagar · Apr 22, 2021

Don Heisz said:
Funny thought to add PhotoFlo to developer.

Nothing funny about adding photoflo to bath A. It's done routinely with divided Pyrocat. In my own experience, it solved some persistent flaws observed in the negatives such as random stain spots. Never needed to use Photoflo for Thornton's two bath but then I always used gentle inversions in bath B.

Avoiding bromide drag in two-bath developers

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