D23 - Sodium Sulfite or Sulfate ??

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pentaxuser

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Yup. D76 outperforms D23 and the ingredients cost less (becuase HQ is MUCH less expensive than Metol/Elon).
D76 makes D23 a historical curiosity.

Doesn't that make Ilford's Perceptol a historical curiosity as well? From what I've seen of John Finch's videos on it it looks to do a very job of developing

pentaxuser
 

Donald Qualls

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Ilford's Perceptol a historical curiosity as well? From what I've seen of John Finch's videos on it it looks to do a very job of developing

So does D-23, from my experience.
 
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mm I tend to differ; imo the superadditivity of the MQ especially the Q has an increasing 'snap' into the highlights, where D-23 can get a nice roll-off at the top. You may not appreciate this small characteristic, and for the most part I think for most average scenes over most of the tonal range D-23/D-76 could be considered equivalent, but for the occasional shooting conditions I encounter for very bright beach/ocean zones the softening of the upper zones is very much welcome.

My story about saving the remainder of an unused gallon jug of D-76 was to give a measured amount of time for the Hydroquinone to rise in Ph so that the D-76 could be used for pushing rolls, and when another photographer gave what he thought was Normal development with 'Hot D-76' he got negs that were very dense. I think I saved his ass(ignment) with a pretty aggressive Farmer Reducer session, and my obvious logic of 'well duh he used from the jug that clearly States "for Pushing" but like I said the end result was stocking Tmax developer for pushing which I was more happy about for pushing.

The paper's darkroom was in a good temperature controlled area so the storage of the older jugs of D-76 could be monitored with a day count, I seem to recall it was at least 2-3 weeks older D-76 in partially filled jugs that I'd use; 4 weeks was too much and 1 week was too little.
 

pentaxuser

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Thanks Christian. I may have read what you have written about D76's increasing pushing ability with time due to the rise of the PH . I have read so much here on Photrio that inevitably I have forgotten some of what I read but I don't think I was aware of this aspect of D76

Presumably what this means is that unless you use all of your mixed D76 in about a week you then need to make appreciable reduction in development times for "box" speed, certainly after 2 weeks at the most

Do the Kodak instructions for using D76 include a reference to this phenomenon?

Thanks


pentaxuser
 
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BradS

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Doesn't that make Ilford's Perceptol a historical curiosity as well? From what I've seen of John Finch's videos on it it looks to do a very job of developing

pentaxuser

I never said nor meant to imply that D23 wasn't a very good developer. In fact, it is a very good developer....it's just that D76 is at least as good (D76 can do what D23 does and more) and commercially packaged D76 is less expensive than home brew D23.
 
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albada

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More importantly, packaged D-76 outperforms home-mixed D-76 (due to the latter's pH change over a period of a week).

Here's a quote from a posting in photo.net about the rise in activity of D-76:

In reading a paper by John Sexton about T-Max films he states "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." I wonder if this is not the increased activity that is being attributed to a rise in pH?​

He attributes the rise in activity to the formation of HQMS and not due to rising pH. Does anyone know whether this is true?
I've always wondered about this supposed rise in pH. D-76 is buffered by borax, so what could cause its pH to rise?
 
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More importantly, packaged D-76 outperforms home-mixed D-76 (due to the latter's pH change over a period of a week). Combine that with the discounts that come with buying chemicals by the train car load, and you find commercial D-76 costs hardly any more than home mixed, and it's more consistent and less prone to measurement errors and "Did I already mix in the metol?"

There is one significant advantage of D-23 over D-76: hydroquinone is a known or suspected carcinogen, and it's not present in D-23. Mind you, photographers don't have the kind of cancer rates organic chemists do, but it's there none the less.
Woah😱

No wonder no one is willing to ship hydroquinone to me!
 

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Combine that with the discounts that come with buying chemicals by the train car load, and you find commercial D-76 costs hardly any more than home mixed
Agreed. Especially if I mix the gallon size (10.42€ at fotoimpex) and my soft wine pouch is a good enough Oxygen barrier over the X months it takes me to use 1 gallon.
More importantly, packaged D-76 outperforms home-mixed D-76 (due to the latter's pH change over a period of a week).
  • Are you referring to home-mixing the original D-76 formula (2g borax) or the buffered version D-76D (8g borax + 8g boric acid)?
  • I once monitored the pH (don't remember whether it was packaged D-76 or home-mixed D_76D) over several days after mixing and did not see any change down to 0.02 units (definitely not claiming that absolute accuracy, just relative change).
 

Anon Ymous

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Here's a quote from a posting in photo.net about the rise in activity of D-76:

In reading a paper by John Sexton about T-Max films he states "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." I wonder if this is not the increased activity that is being attributed to a rise in pH?​

He attributes the rise in activity to the formation of HQMS and not due to rising pH. Does anyone know whether this is true?
I've always wondered about this supposed rise in pH. D-76 is buffered by borax, so what could cause its pH to rise?

Actually, both are correct. HQMS is actually a mild developing agent, much milder than hydroquinone. But it is produced by the reaction of p-benzoquinone in the solution with sodium sulfite, which is already present. P-benzoquinone isn't an ingredient of D76, but an oxidisation product of hydroquinone. When p-benzoquinone reacts with sulfite, HQMS is produced, but also sodium hydroxide. So yes, in a way HQMS synthesis makes D76 stronger, but it's the hydroxide that does the job. Now, if you use the D76d formula, which uses a borax - boric acid buffer, the effect might be smaller. To be honest, I've used old D76 many times and never really saw any difference, although I keep it in full, tightly capped bottles. And I've never mixed the original D76 formula. Ready made D76 is also supposedly better buffered.
 

pentaxuser

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We seem to have different experiences here. Some notice the appreciable difference in contrast such as Christian who noticed what sounds like an appreciable increase in speed and others not so. The appreciable increase appears to be backed by John Sexton but in his case he mentions a month rather than a week to a fortnight but clearly John Sexton's experience was serious in terms of contrast

It might be nice if we can get to the bottom of this. From what I have read it appears:

1. That from 2 sources( J Sexton and Christian) the contrast of what appears to be Kodak manufactured D76 increases substantially and noticeably over 2 weeks but others have seen no difference. J Sexton quotes a half full bottle about a month old so is the change related to the amount of air or is this a "red herring"

2 That from one source (Christian) D76 improves its pushing ability over 2 weeks

However it might be that only home-made D76 is liable to this increase in contrast?

I have no experience with D76 but have experience with ID 11 which is said to be the same thing but is it different enough in at least behaviour in respect of contrast? I certainly never noticed any change in its behaviour over even a few months

pentaxuser
 

bernard_L

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or is this a "red herring"
If this is real, how come the entity previously known as Eastman Kodak, that gave so detailed directions:
KODAK Publication No. J-78
  • times for small (30s agit.) and large (1min agit.) tanks, rotary processor;
  • warning when processing one 35mm film in less than 16 ounces (473ml) of 1+1 diluted dev;
  • conservative limits on capacity and storage duration...
How come they do not mention this increase in activity. A previous version of that rumor was "you need to wait 24 hours". Now it is 2 weeks. Does any one has documented, reproducible experimental data, not plausibility arguments?
 

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IIRC, the "wait for 24 hours" warning used to be part of the mixing directions on the packaging, but that recollection may be unreliable as it is from a long time ago.
FWIW, it was always more relevant to commercial labs, who are/were most interested in process consistency. It may be that the modern product reflects improvements that make the "waiting" unnecessary. That would make sense, particularly since D-76 Replenisher is no longer made.
It does remain necessary to wait until the mixed solution cools to your targeted working temperature.
 
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Ok quick clarification; The D-76 used in my anecdote was Kodak packaged, not formula mixed. The 'well-aged' D-76 would be less than 1/3 full in plastic gallon jugs, and would be kept for 2-3 weeks after the week it was mixed.
That 'well-aged' juice would be used for pushing, however! Just doing Normal processing wouldn't give some huge instant ISO boost, I was using it as the pushing developer and would make appropriate adjustments to the processing time. Normal processing would probably increase the density to perhaps 1/2 to 3/4 of stop denser and looking very contrasty, but the photographer was on a deadline and went through the motions of his usual procedure. I would say that the super dense negs he got was a great example of several small compounding errors made a larger cumulative fail.

I recall that John Sexton advice on T-Max films, and his insights made me stop chasing Tmax 400 around the room ha. The paper had recently switched from Tri-x to Tmax and the whole imaging process needed fine tuning, I still feel that the first version of TMax was much more 'twitchy' in regards to processing, and each of the paper's shooter's needed to fine tune their procedure to bring the quality up. One shooter didn't switch to Tmax for at least a year, he preferred Tri-x and had that film dialed in for his shooting. Once I took Sexton's advise and started using D-76 1:1 with Tmax 400 I felt I had a better control of it, that early version of Tmax seemed to block up the highlights quite quickly. If the light shifted or you made an exposure error of more than 1/3 stop and your processing was +10-15% over you would have a rough day of printing for deadlines.
 

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I think the 24 hrs wait mentioned by 2 members has little or no relevance to the perceived increase in contrast mentioned by either J Sexton or Christiaan( apologies here for failing to notice that your name Christiaan has 2 "As" not one.


We now know that Christiaan's D76 was the commercial one and that his push using was achieved by 2-3 week old D76 and with an appropriate time increase but I had assumed this time increase for pushing was there anyway.

His belief is that normal D76 processing results in a 1/2 to 3/4 stop increase in contrast What isn't clear to me is why the 1/3 full plastic jugs of D76 was need for pushing when I assume normal D76 did not have the same effect

Can I ask Christiaan for further clarification here: By normal processing what do you mean? Do you mean that the same time increase for pushing using D76 that was 2-3 weeks old but was still in full bottles so not 2/3rds empty would have failed to have the same effect as your 1/3rd full container of the same age?

Or that even a full bottle of D76 would have had the same effect as the 1/3rd full container had the full one been the same age?

We also have the very relevant point made by bernard L that Kodak makes no mention of this phenomenon which one would think it would make if it had seen any signs of it. It still remains quite a puzzle in terms of drawing general conclusions


Thanks

pentaxuser
 

bernard_L

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Ok quick clarification; The D-76 used in my anecdote was Kodak packaged, not formula mixed. The 'well-aged' D-76 would be less than 1/3 full in plastic gallon jugs, and would be kept for 2-3 weeks after the week it was mixed.
That 'well-aged' juice would be used for pushing, however! J
Indeed. Old or well-used D-76 first goes through a phase of high pH and high activity, before dying completely. But that is quite different from the alleged initial rise in activity of freshly mixed D-76 over hours? days? weeks?

Of course one has to wait until it has cooled down. To gain time, instead of adding the final 200cc of cold water (for 1000cc final) use ice cubes😎
 

albada

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Actually, both are correct. HQMS is actually a mild developing agent, much milder than hydroquinone. But it is produced by the reaction of p-benzoquinone in the solution with sodium sulfite, which is already present. P-benzoquinone isn't an ingredient of D76, but an oxidisation product of hydroquinone. When p-benzoquinone reacts with sulfite, HQMS is produced, but also sodium hydroxide. So yes, in a way HQMS synthesis makes D76 stronger, but it's the hydroxide that does the job. Now, if you use the D76d formula, which uses a borax - boric acid buffer, the effect might be smaller. To be honest, I've used old D76 many times and never really saw any difference, although I keep it in full, tightly capped bottles. And I've never mixed the original D76 formula. Ready made D76 is also supposedly better buffered.

Thanks for posting this explanation. As a check on my understanding, I'll summarize it in my words:
  1. Oxygen oxidizes hydroquinone.
  2. Oxidized hydroquinone produces p-benzoquinone.
  3. P-benzoquinone reacts with sodium sulfite to produce HQMS and sodium hydroxide.
  4. Sodium hydroxide raises the pH.
Hopefully I got that right.

This brings up another question: PQ developers contain hydroquinone, so why do we not hear about their pH rising? Are they buffered better?
 

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Thanks for posting this explanation. As a check on my understanding, I'll summarize it in my words:
  1. Oxygen oxidizes hydroquinone.
  2. Oxidized hydroquinone produces p-benzoquinone.
  3. P-benzoquinone reacts with sodium sulfite to produce HQMS and sodium hydroxide.
  4. Sodium hydroxide raises the pH.
Hopefully I got that right.

This brings up another question: PQ developers contain hydroquinone, so why do we not hear about their pH rising? Are they buffered better?

Yes, that's pretty much it.

You have an interesting question about the rest of the PQ developers. If I had to make a guess, I'd say they're just as susceptible as D76 is, if buffered to the same extent. The reason we don't hear that much about it is probably because they've never been as popular as D76, nor put under so much scrutiny.
 
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Ok well this has me applying some compressed air to the cobwebs.

In regards to this 'aged D-76', during this period 'Normal' processing was done with the weekly mixed fresh gallon of D-76, using normal times. The weeks remainder of D-76 I would pour off into the other jug (clearly marked ha), and I'd let that 'season' for at least 1-2 weeks before (personally) using that seasoned D-76 as the pushing developer. The aged D-76 would not be used for Normal shooting and ISO ranges. Most of the time the remainder of the Normal D-76 would be less than 1/2-1/3 of a gallon.

At this point I had stopped actually trying to identify 'correct' ISO for the poor lighting I mentioned, so my Exposure Index/ Processing ISO was based on the location, for example one football field would be a 16 minute processing whereas another darker field would be 19 minutes and I think the darkest would be over 22 minutes. The goal was to use the aged D-76 for those maximum pushes after the upward shift in Ph but before the regular fall in D-76 activity as mentioned.

As I might have inferred, this little system worked pretty well for a short time, but it needed a higher level of attention and consistent practices to keep it going and working well. And as I mentioned, after the 'blown roll' I had to stop. The shift to using Tmax developer ended up being a better solution for the pushing of TMax P3200, it was obviously more consistent and the results were much better, with the TMax Developer having a nice ability to retain more printing ability in the sometimes strong highlights, and I could also nudge Tmax 400 to 2500/3200 E.I. pretty easily.
 

Alan Johnson

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This brings up another question: PQ developers contain hydroquinone, so why do we not hear about their pH rising? Are they buffered better?
I suggest that because there is usually only about 1/10 the quantity of phenidone compared to metol it may not react with air 10x as fast which would be needed to produce the same amount of benzoquinone and hydroxide from the hydroquinone so the pH would not rise to the same extent.
 

pentaxuser

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Incidentally for anyone interested in XRay film sheets, Andrew O'Neill's latest video about his 14x17 X Ray neg which he developed in D23 1+1, suggest to me that it is a pretty good developer for X Ray negs .

pentaxuser
 

Donald Qualls

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I suggest that because there is usually only about 1/10 the quantity of phenidone compared to metol it may not react with air 10x as fast which would be needed to produce the same amount of benzoquinone and hydroxide from the hydroquinone so the pH would not rise to the same extent.

What does the quantity of metol or phenidone have to do with oxidation of the hydroquinone?

IMO, it's much more likely that PQ developers are just better buffered than (1930s vintage formula) D-76.
 

Alan Johnson

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What does the quantity of metol or phenidone have to do with oxidation of the hydroquinone?

IMO, it's much more likely that PQ developers are just better buffered than (1930s vintage formula) D-76.

Yes, you are probably right, ID-68 with phenidone has about 4.5x as much borate as does D-76 with metol.
I was speculating that phenidone/metol oxidation might be the first stage in air reduction as it is with silver bromide reduction .
Oxidation of hydroquinone would then be the second stage. I never saw any discussion of this though.
 
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