Leader Density: D-76 vs Rodinal and others

[Thomas Bertilsson]

One more piece of information: the pH of the Kroger distilled water measured between 5.2 - 5.5 pH. Tap water measured between 7.5 -7.8 and the bottled drinking water I used to mix the 76 came in just a smidge above 7.8.

Distilled water isn't even close to the 6.5 - 7.0 I expected!

I also found a thread from '09 where PE also indicated that distilled water is acidic. Since 76 is only around pH 8.5, mixing with distill water would certainly seem to be capable of degrading 76, especially when diluting 1:1 with distilled.

This might also explain what was constantly killing my Xtol in just a week or two, in addition to the DO.

Wow. That's interesting, and very odd. But it sure does explain a lot of things. I would think both D76 and Xtol would be buffered to withstand fluctuations in water quality, but that's a big difference you're showing.

 

[Arvee]

Wow. That's interesting, and very odd. But it sure does explain a lot of things. I would think both D76 and Xtol would be buffered to withstand fluctuations in water quality, but that's a big difference you're showing.

Kinda blew me away too! In PE's thread, he indicated that the distillers are descaled/cleaned with sulfamic acid or phosphoric acid. Perhaps that's why it is so acidic.

 

[Arvee]

I would have thought the pH of any water can drop as it absorbs gases such as CO2. Perhaps distilled/deionized water can drop slightly more. But since water has virtually no buffering strength I'd have still expected this to have an insignificant effect on even weakly buffered developers. And XTOL is fairly well buffered.

Not a chemist, Michael, but extremely frustrated with D76 that progressively weakens from day one and Xtol that would go off anywhere from a week to three weeks. Been using the same brand of distilled water from my local market for over 10 years now and the last batch of 76 was mixed with bottled water and has been holding well; no evidence of weakening so far (getting close to 10 rolls). No problems with any liquid developers, just the ones in powder form including mixing from scratch.

Did the due diligence on HDPE containers (in which most distilled water is packaged) and their propensity to absorb oxygen through the container wall. Then I came across PE's thread on DW's pH typically being acidic and decided to measure the pH of my water options. Since my choice of water appears to be the Red X there has to be some characteristic of the DW that is causing my developer to go off. DO and acidic pH are the two likely candidates but, as I said, I am no chemist beyond college chemistry.

Please feel free to offer an opinion if you have any thoughts on the problem.

 

[pentaxuser]

extremely frustrated with D76 that progressively weakens from day one and Xtol that would go off anywhere from a week to three weeks. Been using the same brand of distilled water from my local market for over 10 years now and the last batch of 76 was mixed with bottled water and has been holding well; no evidence of weakening so far (getting close to 10 rolls). No problems with any liquid developers, just the ones in powder form including mixing from scratch.


Please feel free to offer an opinion if you have any thoughts on the problem.

Fred,I too am a non chemist but it may be the case that liquid developers hold up because the only water used is that for the dilution and then is used instantly whereas the powder stuff sits in the suspect water for a long time while being slowly used up. Mind you if the water from your local market is the same as that used for powder and has been holding well this kind of destroys what I have just said:confused:

pentaxuser

 

[Arvee]

Fred,I too am a non chemist but it may be the case that liquid developers hold up because the only water used is that for the dilution and then is used instantly whereas the powder stuff sits in the suspect water for a long time while being slowly used up. Mind you if the water from your local market is the same as that used for powder and has been holding well this kind of destroys what I have just said:confused:

pentaxuser

Your conclusions are spot on! I switched from distilled water in HDPE containers to bottled drinking water in PETE containers which has a pH of 7.8. I am confused about what the culprit is but the developer is holding up with the new water.

I came to the same conclusion you did about the powder developers sitting in 'bad' water and slowly oxidizing/heading to depletion. Like you said, the liquid counterparts use far less water, are mixed immediately prior to development and are actively developing before any real degradation can occur. I have my fingers crossed this solves the problem and I can get back to making photographs!! D76 has been my dev of choice for many years without difficulty.

 

[Bill Burk]

One more piece of information: the pH of the Kroger distilled water measured between 5.2 - 5.5 pH. Tap water measured between 7.5 -7.8 and the bottled drinking water I used to mix the 76 came in just a smidge above 7.8.

Interesting.

I only have test strips and a color chart to compare. But my water, both tap and Reverse-Osmosis-Filtered appear to be around 5 pH.

As I have explained, my development times (though consistent) are always relatively long in D-76 1:1 compared to published charts. Maybe this is why.

 

[Gerald C Koch]

What always seems to get lost in any discussion of pH on APUG is buffer capacity. Which is defined as the measure of the resistance of a buffer solution to pH change upon addition or removal of hydrogen ions. Pure water has NO buffer capacity and tap water has VERY little. So forget water differences as an explanation whether it be impurities or ozone or fluoride, .... Such explanations are what in German is aptly called Quatsch mit Sosse which translates as "nonsense with gravy on it."

As far as what the OP poster observed may I add that visual density is very different from photographic density. Different developers may produce different visual densities. This does not mean that there is anything wrong with them. As long as the OP is satisfied with his negatives then there is no problem.

 

[Arvee]

To restate the issues so those who missed the finer details of the problem:

1) This problem of D76 leaders being weak (looking more like coffee stains than being opaque) and Xtol dying within a couple of weeks has occurred repeatedly over the last 8-9 years with the fresh lots coming from Freestyle (Arista 76), 5+ gallon bags; BHPhotoVideo (Kodak D76), approx 15 gallon bags; and 10 5L Xtol bags from Freestyle and BH. All of these were mixed with the Kroger DW exclusively.

2) No liquid developer has ever exhibited less than an opaque leader when developed to manufacturer's recommendations, including, but not limited to, 3 bottles Tmax, DDX, 3 bottles of HC110, 3 bottles of Rodinal 500ml. Kroger DW was used with all these developers over the past same time period.

3) Wet prints made with D76 developed negs are always FLAT compared to the liquid developers, pretty much consistent with the weak densities in the leaders and highlight densities. Recent measurements using a spot meter as a densitometer confirm 3 stops difference between a D76 leader and a Rodinal leader, both developed to mfrs. specs. Using one poster's suggestions, I was able to determine that the D76 leader developed normally only reached D=2.1 where the Rodinal leader reached 3.1+ when developed normally. Negs exposed using Sunny 16 at box speed or 1/3 stop less and developed to Kokak's specified times, straight and 1:1. Minimum 250ml or more per 80 sq. in. Negative material includes both 100 and 400 speed film.

4) Bottled drinking water used for mixing D76 for the last 8 rolls have show a leader opacity differential from Rodinal about 0.5 stop. I just got back from vacation in S. Utah and have over a dozen rolls to process and will see if the rest of the gallon and the new batches work as advertised.

5) I don't own a densitometer but have employed my Pentax spot meter as a makeshift densitometer.

6) Bottom line question: Why should D76 exhibit 3 stops less density in its leader (and Xtol die anywhere from 3 days to two weeks) when mixed with Kroger DW when no liquid developer exhibits less than virtual opacity? Why would bottled drinking water with pH of 7.8 when mixed with D76 have caused the leader density to increase by 2.5 stops?

I don't know the answer; I only know the bottled drinking mixed with D76 has improved results comparable to results in the 90s when I lived elsewhere and used tap water and worked with fully developed negs.

My curious nature now wonders why?

 

[Xmas]

The faucet water here is very hard but I use it for ID11 Microphen and ID68, the first two as one litre packs from Ilford the last raw chemicals.

Not had it go off yet but I use it in less than 2 months as stock 10% longer per film.

I boil the faucet and mix with cold to get to mix temperature to dissolve the powder which softens it a bit.

Do the Kodak packs mandate distilled?

 

[Gerald C Koch]

Do the Kodak packs mandate distilled?

No, Kodak incorporates as calcium chelating agent in its packaged developers. Water hardness should have no effect.

 

[Gerald C Koch]

To restate the issues so those who missed the finer details of the problem:

1) This problem of D76 leaders being weak (looking more like coffee stains than being opaque)

A fine grain developer like D-76 or Xtol may produce silver grains that appear brown and transparent rather than black and opaque such as produced by more active developers. This goes back to my comment on visual density as opposed to photographic density. A similar effect occurs with negatives produced by stain (pyro) developers. Such negatives appear thinner to the human eye (and even a camera's light meter) yet print correctly.

Some years ago Kodak stated in one of its publications that any water that was suitable for drinking was suitable for its developers. As I said before water has little or no buffer capacity and its pH will have no effect on the pH of the developer.

Considering water containing carbon dioxide from the air. If the carbon dioxide in the water is in equilibrium with the carbon dioxide the air then such water would contain 0.6 mg of carbon dioxide per liter. Far too low a concentration to have any effect.

The only thing which would cause Xtol to fail prematurely would be iron (III) or copper (II) ions in the water. BUT Xtol for a number of years has contained a chelating agent DTPA to prevent this.

 

[Thomas Bertilsson]

I'm starting to think that the Kroger demineralized water needs to be analyzed.

Gerald, are there no other known ways to kill developer activity with Xtol other than iron and copper ions? No pollutants, or something perhaps from the bottles?

 

[Thomas Bertilsson]

I still find this very strange. The water would have to be seriously bad. The Fenton reaction is what can theoretically bust XTOL by destroying the ascorbate. But as has been noted already packaged XTOL contains sequestering agents for this and other purposes. And even still, that wouldn't explain low D-76 activity since it doesn't contain ascorbate. For these particular packaged products to have lower than normal activity upon mixing (assuming the dry materials were fine), you'd need some kind of oxidizing compound in the water, and in material quantities. Or something which would lower or neutralize the alkalinity of the developer to a significant degree - some sort of significant acidic compound perhaps. But even then, XTOL in particular is buffered. D-76 to a lesser degree but still. Unless the water contained some compound which destroyed borates or sulfite by some other mechanism/reaction (since those are the only things XTOL and D-76 have in common).

I don't know, maybe Gerald will have some ideas, but this would have to be some very bad water. I'm still not buying this. There has to be another explanation. All things considered these developers (the packaged commercial versions) are quite robust.

I can't speak much for D76 since I have only used it for a couple of months now. I've mixed and used about four or five gallon kits now, with boiled tap water cooled to appropriate mixing temp. I have a batch of D76 now that's a few weeks old and I can't tell any change in activity compared to one day after mixing.

Xtol, well I used and mixed it in three different darkrooms over the years, using distilled water, reverse osmosis water, and tap water. Boiled and not boiled. Some of the stock solutions were stored for a very long time, and the replenished working solution once sat for six months without actually developing any film. I just replaced about 100ml per month with equally old stock solution. That developer never skipped a beat regardless of how I mixed or stored it. Standard plastic brown DataTainer bottles and *gasp* accordion bottles for the replenisher (they are supposed to be terrible).

Something's very fishy here, but if that demineralized water is the only common denominator, it would be wise to abstain from using it. However, if the problem comes up again, then nothing was really solved and we're patching symptoms instead of getting to the root cause.
I find it incredible that all liquid concentrate developers are fine, as well as the powders not mixed with that Kroger water. The only one that have failed are the ones mixed with Kroger water. As strange as it sounds, it's hard to think of another common denominator.

 

[Arvee]

I've gotten a serious brain cramp pondering this issue. As said before, I will be processing more than a dozen rolls in the next couple of days and will report results on those films.

Gerald, I was hoping that someone would be processing a roll or two in 76 and could give a comparative analysis of leader density; preferably numbers from a densitometer would be ideal. With D76, brown leader is something I do not ever recall seeing over the last 30 years of using the product.

Off to soup....

 

[Thomas Bertilsson]

Now I kind of wish I still had some 35mm Tri-X. I'd be happy to send you all and any leaders from processing that film, but I stopped using it in favor of HP5+. If you can use any of those leaders with D76 I'd happily send them to you.

 

[Xmas]

I drink my faucet water, id not drink deionized.

Why are you using deionized for mono developers?

 

[Arvee]

Now I kind of wish I still had some 35mm Tri-X. I'd be happy to send you all and any leaders from processing that film, but I stopped using it in favor of HP5+. If you can use any of those leaders with D76 I'd happily send them to you.

Thomas, a quick check is can you hold your developed leader up to your eye while outside and see through it? Most of my leaders dev'd in liquid I cannot see but the faintest detail through the leader; the leaders dev'd in 76 with this new batch are just very slightly more translucent than the liquid dev'd leaders.

Negs will be going into the dryer in another few minutes. I will have a report after they dry.

Report: snip test shows excellent leader density. Negs, not yet dry, look excellent also.

 

[Gerald C Koch]

I'm starting to think that the Kroger demineralized water needs to be analyzed.

Gerald, are there no other known ways to kill developer activity with Xtol other than iron and copper ions? No pollutants, or something perhaps from the bottles?

The only substances that I have ever seen mentioned are iron and copper ions. Years ago there was a long discussion on pure-silver on the Fenton reaction. This was when Ryuji Suzuki was formulating his developers. At the time he used salicylic acid (which chelates iron) in combination with TEA (triethanolamine which chelates copper) due to the unavailability of other chelating agents. Not everyone can use a ton of DTPA.

 

[Thomas Bertilsson]

Thomas, a quick check is can you hold your developed leader up to your eye while outside and see through it? Most of my leaders dev'd in liquid I cannot see but the faintest detail through the leader; the leaders dev'd in 76 with this new batch are just very slightly more translucent than the liquid dev'd leaders.

Negs will be going into the dryer in another few minutes. I will have a report after they dry.

Report: snip test shows excellent leader density. Negs, not yet dry, look excellent also.

Fred, next time I develop film I will check the leader for sure. I only have HP5+ film, but I think as far as developer activity goes that is probably almost irrelevant.

Probably processing some film tomorrow.

 

[Thomas Bertilsson]

The only substances that I have ever seen mentioned are iron and copper ions. Years ago there was a long discussion on pure-silver on the Fenton reaction. This was when Ryuji Suzuki was formulating his developers. At the time he used salicylic acid (which chelates iron) in combination with TEA (triethanolamine which chelates copper) due to the unavailability of other chelating agents. Not everyone can use a ton of DTPA.

Thanks, Gerald.

 

[Arvee]

Ok, folks, I have done 8 of 13 rolls and results are full scale, richly developed negs, something I haven't seen with 76 in a mighty long time!

As far as I am concerned the Red X is definitely the water but perhaps there is some hidden aspect of the Kroger DW creating the problem. Perhaps something in the DW that is depleting the buffering capability of the developer?

Anyway, I'd be pretty happy just going merrily on my way continuing to use drinking water and forgetting about this whole situation!! If I never find out, it won't keep me up nights worrying about it!!!

As one poster said, "Trust nothing!"

 

[MattKing]

Is there anything remarkable about the container that the Kroger water arrives in, or that you are using to store it?

 

[Arvee]

As noted in earlier posts, most DW containers are made of HDPE plastic which is gas permeable and readily absorbs O2 from the atmosphere. I store mixed chems in 5L brown glass bottles until decanted into 500ml brown glass Boston rounds.

Is there anything remarkable about the container that the Kroger water arrives in, or that you are using to store it?

 

[Sal Santamaura]

As noted in earlier posts, most DW containers are made of HDPE plastic which is gas permeable and readily absorbs O2 from the atmosphere...

It would be most interesting if the chemists among us post their take on how much oxygen diffuses into water. Let's assume the container is more than permeable -- make believe it's uncapped and open to the atmosphere. If boiling drives out all/most oxygen, at what rate would it return? What's the forcing function(s)?

 

[Gerald C Koch]

The solubility of oxygen in pure water is 18 mg per liter @ 20C. It would be even lower in a solution containing a large amount of dissolved chemicals like D-76 < 14 mg per liter. Far too little to have any meaningful effect. I have made up developer for 60 years without boiling the water and never experienced any difficulties.

As a chemist I can find no reason that the Kroger water should have any effect on D-76. Speculation is futile. Forgive me Jean-Luc.