D-76 gaining strength... Whaaaaat?

pbromaghin · Jul 28, 2018

My son-in-law sent me this screenshot from "the darkroom group" on "social media" (would that be facebook?).

What are they talking about?

mshchem · Jul 28, 2018

I have cans of D-76 from the 60's, easily reach iso of 32,000 with Tri-X.

Bill Burk · Jul 28, 2018

Sure people have said that.

The effect of increasing activity over time has a basis in chemistry, so you will find a valid explanation.

I don’t think it’s a huge issue.

I check contrast all the time and I often use old D-76. Sometimes over a year of age since mixed. I suppose I could plot my historical time contrast data points versus age of developer... I keep notes on that.

But the impact is not huge, I never feel like age of D-76 causes my processing to get out of control.

It’s certainly not something to worry about in normal day to day work. But if you are establishing your controls. Then you should use D-76 either immediately or after a fixed time (like maybe 24-hours after mixing). Because when establishing controls you want to eliminate as many variables as possible.

Bill Burk · Jul 28, 2018

Alan Ross wrote about it rather clearly in one of his blogs. I can’t find it right now but you might browse his writing.

RPC · Jul 29, 2018

I believe PE has explained that the pH goes up during 2-3 days after mixing. Reactions produce sodium hydroxide which is the cause of the rise. I believe he has said that this happens to a degree in all developers containing hydroquinone, not just D-76. I have experienced quite an increase in contrast myself and always wait a few days after mixing before using. I don't know why one would have to wait a year.

Guilherme Mauricio · Jul 29, 2018

Hello there. New here.

I remember in Anchell's "The Film Developer Cookbook" he says something about hydroquinone and the pH in D76, and for that reason he recommends D76H which is a slight modification of the formula.
I don't think it's available off the shelf, though.

But as described in the book, I thought my negs would come out black if using a developed mixed maybe one or two years before. Glad to know it's not that wild.

Ian Grant · Jul 29, 2018

RPC said:
I believe PE has explained that the pH goes up during 2-3 days after mixing. Reactions produce sodium hydroxide which is the cause of the rise. I believe he has said that this happens to a degree in all developers containing hydroquinone, not just D-76. I have experienced quite an increase in contrast myself and always wait a few days after mixing before using. I don't know why one would have to wait a year.

Most powdered film developers should be left overnight after mixing before use, that allows the equilibrium products to form and give a balanced developer and let the pH settle.

The sudden rise in activity with a drop in shadow detail happens just before D76 and similar developers collapses, it's more typically seen in replenished developers where the Bromide build up inhibits the Metol. However there's another issue over time the Hydroquinone slowly forms HMS - Hydroquinone monosulphate which changes the pH and increases the activity, this happens in both stock solution stored too long. The change is sharper and more noticeable with Replenished D76/ID-11 and would also occur in any other Replenished MQ film or paper developer, it's not unique to D76. To keep this too a minimum Kodak changed the buffering of D76 to something closer to D76d, it's likely Ilford also changed the buffering in ID-11

Ilford's commercial PQ variant of ID-11/D76, Autophen didn't suffer these issues and had a very long life when replenished, one lab keeping the same developer going for a number of years. Unlike D76/ID-11 Autophen wasn't affected by bromide build up as Phenidone can tolerate significantly higher levels than Metol and buffering similar to D76d, so replenishment could be on a top up system which is far more economic.

Bill, I think you might have AA's wrong assistant in mind, it's John Sexton that's written about increased activity of D76.

Ian

Ian C · Jul 29, 2018

Here are John Sexton’s comments from his 1987 article A few ideas on using Kodak T-Max Films Successfully.

Here is the relevant paragraph.

“NOTE: If you use D-76 developer be sure to use FRESH D-76 (not some that has been sitting around in a half-full bottle for a month!) As D-76 ages a chemical compound, hydroquinone monosulfonate, is formed. This chemical compound will INCREASE the activity of the developer and the contrast of your negatives in a big way with T-MAX. When mixing a gallon of D-76 I suggest storing it in 4 one-quart glass bottles filled to the brim. In this way you can work out of one bottle while the others remain full to minimize oxidation. If in doubt about the age of chemical ... dispose of it. There appears to be no similar aging problem with the T-Max system of developers.”

http://www.largeformatphotography.info/articles/sexton-tmax.html

Ian Grant · Jul 29, 2018

D76 doesn't age in a month, it takes more than six months, more like a year, before you'd see an issue unless it's been stored badly. In some cases it last longer.

Ian

Photo Engineer · Jul 29, 2018

Grant Haist describes this in his book. I suggest reading the entire 2 volume set to those interested in this type of problem.

Basically, activity goes up over about 3 days according to Grant, and then stabilizes more or less over the life of the developer. This is due to the pH rise causing activity to go up, and then it goes down as more HQ is used up to make HQMS. It finally stabilizes, and then begins to decrease over an extended period as the developer ages.

This is true of all HQ developers, again according to Grant.

PE

Bill Burk · Jul 29, 2018

Now I regret not fixing that old pH meter I got at a print shop auction years ago... would be great if my notes had pH too.

Yes, it was John Sexton who wrote about this effect. I sure got my Ansel Adams' assistants mixed up. They seem to get more active over time too.

RPC · Jul 29, 2018

So, PE, to be clear, the formation of HQMS does not cause the rise in pH, but sodium hydroxide, or something else?

Photo Engineer · Jul 29, 2018

Basically, yes, NaOH is the final product and it raises the pH just a tiny bit, but as more HQMS forms, the activity drops due to the fact that HQMS is a less active developer than HQ. See Haist, V1 for the explanation in detail. It is hard to express without graphics.

PE

Ian Grant · Jul 29, 2018

Photo Engineer said:
Grant Haist describes this in his book. I suggest reading the entire 2 volume set to those interested in this type of problem.

Basically, activity goes up over about 3 days according to Grant, and then stabilizes more or less over the life of the developer. This is due to the pH rise causing activity to go up, and then it goes down as more HQ is used up to make HQMS. It finally stabilizes, and then begins to decrease over an extended period as the developer ages.

This is true of all HQ developers, again according to Grant.

PE

A question on a different Forum about Pyrocat HD is actually quite relevant here. The question was about longevity but I also posted about how it changes after mixing.

Now Pyrocatechin is very prone to oxidation, as is Metol but a bit less so, when mixing a developer, so when I made a new batch of Pyrocat HD Part A (dev agents Metabisulphite & Bromide) this afternoon it was a slight reddish colour, It was also slightly opaque, I bottled it and checked it an hour later after taking the dog for a walk, it was clear and a straw yellow colour.

You can see the same making up D76/ID-11 and other MQ - well on fact also PQ - developers, you'll get weak oxidation of the developing agents until reversed by the preservative usually Sodium Sulphite (a mild anti oxidant), Pyrocatechin & Pyrogallol needs a stronger anti oxidant like Metabisulphite.

I don't doubt your comments Ron's comment of Haists findings at all, in the real world we'd dump a replenished tank batch of D76/ID-11 and have no choice but use the new batch the next day, usually we'd seasoned it with some of the previous batch. We all hated using the very fresh developer but that wasn't just for the reasons Ron's mentioned rather that it wasn't fully seasoned, but of course partially this equilibrium balance.

Ian

Arklatexian · Jul 30, 2018

Photo Engineer said:
Grant Haist describes this in his book. I suggest reading the entire 2 volume set to those interested in this type of problem.

Basically, activity goes up over about 3 days according to Grant, and then stabilizes more or less over the life of the developer. This is due to the pH rise causing activity to go up, and then it goes down as more HQ is used up to make HQMS. It finally stabilizes, and then begins to decrease over an extended period as the developer ages.

This is true of all HQ developers, again according to Grant.

PE

I have mentioned this before. I remember studios who used D-76 holding out 4 oz or so of old D76 when dumping the old developer. After mixing new D-76, they would add the 4 oz of old developer into the fresh (1 gal) to "season" it so they could use it right away. Did you ever hear of that?......Regards!

newcan1 · Jul 30, 2018

I have started using the D-76d formulation with great results. It is supposed to deal with the pH-changing issue inherent in the original D76 formulation.

Photo Engineer · Jul 30, 2018

That method of reserving old D76 and adding it to new is not a very good way of starting up, but it is essentially a "starter" solution for the new developer. There are better ways to do it. We just kept using the old stuff with replenishment and rarely mixed new unless a disaster struck.

PE

pbromaghin · Jul 31, 2018

So to sum up the answer to my original question, D-76 needs to sit for a few days and there is some small effect over age, but nothing like the questioner feared nor the answerer made it out to be. If it does happen, it would be in a long-used replenishment batch that is about to collapse. Is that about right?

Bill Burk · Jul 31, 2018

Sounds right to me.

Note. I have only used D-76 in one-shot mode. I have only twice experienced total failure to develop in my life.

I even occasionally use the last of a bottle that’s been open a few weeks.

In case there is any doubt, you can always drop the clipped off end of film in the mixed beaker to see if it darkens in about a minute.

I don’t even try to evaluate “how effective” it is past that point, because I have found it always works well if it works at all.

Ian Grant · Aug 1, 2018

pbromaghin said:
So to sum up the answer to my original question, D-76 needs to sit for a few days and there is some small effect over age, but nothing like the questioner feared nor the answerer made it out to be. If it does happen, it would be in a long-used replenishment batch that is about to collapse. Is that about right?

The initial phase mostly occurs in a few hours, in practice with commercial use we couldn't wait a few days, so over-night was typical, but sometimes over a weekend. There's a noticeable quality difference between negatives processed in fresh D76/ID-11 and the developer replenished once it's seasoned and none of liked it for the first day or so until after a few films had been processed. Liked is probably the wrong term netter to say we preferred it after it became seasoned.

Usually replenished D76/ID-11 would be dumped before it collapsed, the sudden change in activity is easy to spot - we had three photographers using the deep tanks and never lost negatives because of it in well over a decade.

A point being missed is that fresh D76/ID-11 stock solution will also collapse over time, so a shelf life of 6 months once mixed is suggested by Kodak but 9-12 months should be OK if stored properly.

Ian

DREW WILEY · Aug 1, 2018

You either have to standardize on 76 just mixed, or standardize to its plateau from about a week old to six months, provided it's been stored in full glass bottles. I'd divvy it up into small 8oz amber glass bottles sufficient for a single session mixed 1:1. Not my favorite developer, but adequate. Formulary sells a buffered version of it without the drift. I don't replenish anything.

D-76 gaining strength... Whaaaaat?

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