Experiences with Vitamin C developers please

[swmcl]

I'm currently trying to standardise my workflow around a developer that has an amount of Vitamin C in it. Changing from a 1500 series Jobo tank to an Expert tank and changing from roll to sheet film is seeing a drop in ASA of around 1 stop. Given this developer is giving me really slow results from the film anyway the decrease of another stop or so makes it very, very slow.

So you should assume same temp, same film type, same dilution, same developing time, same amount of developer and similar agitation (slow hand rotations on roller base in a tempered water bath). I pre-wash and develop in distilled (not demineralised) water.

The film (FP4) has gone from ASA 40 to ASA 25 or so in the Expert tank. The gradient of the roll of film was 0.47 and the sheet film was 0.3.

I am wondering if there is a problem with Vit C running out of puff. Does a developer containing Vit C go off any differently than other developers ? Does Vit C tend to react more or less with agitation ? Should I really be using another chemical in the developing fluid - like a preservative of some sort ?

The developer is essentially 510 Pyro at 1:200 in TEA.

Having such flukey results means I have no surety in processing at this stage and the terribly slow ASA results are a worry too.

Cheers,

Steve

 

[Gerald C Koch]

Yes ascorbic acid, vitamin C can be subject to the Fenton reaction. This can result in a very rapid loss of developing activity. The reaction is catalyzed by iron and copper ions which can be in the water OR in the chemicals used to compound the developer. Now the TEA will complex copper ions and prevent their action.

That being said, very dilute developers do not respond well to any agitation method that causes an unusual amount of aeration. So it may be the change in developing tank and its use.

Another possibility when changing tanks with very dilute developers is the change in the amount of working strength developer per in2 of film. Notice that what is important is not the total volume of developer in each style tank For example, if you have two tanks each with the same amount of developer but one contains more film than the other you may have difficulties. I would suggest a test trying a dilution of 1:100 rather than 1:200.

I assume that your vit C is fresh and shows no signs of oxidation.

 

[swmcl]

Gerald,

The batch of 510 that I refer to is my second batch. Initially I purchased a special order from the Formulary but it was black when I got it.

This batch was made by me from all fresh and special order chemicals especially the TEA. It is still a weak straw colour today as I used it. I have just walked back into the room after a development session and I think it is even worse than the other day.

I did use a metal extension on the syringe to draw the developer into a syringe before using. I do use stainless steel jugs to mix all my chemicals in. A separate jug for each thing; pre-wash, dev, stop, fixer, wash, etc.

I have done a complete BTZS test with this developer only a month ago and the results were fairly usable at 1:200. The results I have now are shocking. Its as though in the last month or 6 weeks the developer has lost 60-80% of its strength. I was going past 2.4 in density on FP4 ! Now it'd be lucky to hit 1.0.

As 510 has three developers in it how can a Fenton reaction cause such a loss of activity ? Isn't the loss of one agent just a part of the whole thing ? It seems to me that the whole development process is dead or dying.

I believe XTOL is also a developer that - at least in the past - died without notice. Doesn't it also have Vit C ?

I also store all my stock chemicals under nitrogen in amber bottles.

Steve

 

[Gerald C Koch]

The Fenton reaction will not effect the phenidone or the pyrogallol which would explain why you are still getting some image. But if you can eliminate all other variables then the problem is with the ascorbic acid.

 

[swmcl]

Thanks Gerald,

I realise there is a superadditive reaction in there also and that might explain the rapid decline. My question is specifically looking at those developers with Vit C ascorbic because I have the Formulary containers of Pyrocat-HD and I swear they are good for 3 years and that is without any nitrogen.

I'm looking questioningly at the ascorbic vit C as the culprit here and I want to hear of any others who may have this view too.

Cheers,

Steve

 

[Alan Johnson]

http://unblinkingeye.com/Articles/PCat/PCat2/pcat2.html
Here Sandy King discusses the oxidation of Pyrogallol in rotary processors and the advantages of pyrocatechin.
Its not entirely clear that vit C is the cause of the loss of film speed,is there a possibility it may be down to oxidation of pyrogallol?

 

[Rudeofus]

Yes ascorbic acid, vitamin C can be subject to the Fenton reaction. This can result in a very rapid loss of developing activity. The reaction is catalyzed by iron and copper ions which can be in the water OR in the chemicals used to compound the developer. Now the TEA will complex copper ions and prevent their action.

IIRC you need another compound to also sequester iron impurities, Ryuji Suzuki's developers use Salicylic Acid for this purpose, whereas there is no suitable compound in 510 Pyro.

@swmcl: you can test very easily whether the Ascorbic Acid in your concentrate has gone bad: prepare two standard batches of working solution, to one of which you add 0.5 g/l Ascorbic Acid and 0.5 ml/l TEA. Both compounds can be easily sourced locally. Expose two sheets and develop them one in each soup, if the second one shows normal development whereas the first one looks underdeveloped, you know the Ascorbic Acid in your concentrate has gone bad. In this case you can "repair" your developer (but not the concentrate!) until you have prepared fresh concentrate.

 

[Gerald C Koch]

IIRC you need another compound to also sequester iron impurities, Ryuji Suzuki's developers use Salicylic Acid for this purpose, whereas there is no suitable compound in 510 Pyro.

Due to the choice of chelating agents two were needed in Ryuji's formulas. Remember the requirement that any choice be readily available for the average person. The TEA chelated the copper and the salicylic acid the iron. There are chelating agents that will do both but they are either expensive or hard to obtain.

 

[sfaber17]

I have also been having trouble with those developers. Very low activity. Maybe the problem is using a jobo at high rotation since the pyro is always very oxidized at the end as mentioned. Also had trouble with PC-TEA and Pyro Uno. I'm wondering if the vit. C is any good - new from Formulary. I made a NaAscorbate developer LSD-6, using and it was very active. However that has sulfite and may be better with a jobo. I think I'll try titrate with iodine to determine if the pyro and vit. C is good, and try in a manual tank.

 

[Rudeofus]

sfaber17, can you confirm that your Pyro/Ascorbate developers were a lot more dilute than this (there was a url link here which no longer exists)? This may explain quite a bit ...

 

[sfaber17]

Good point Rudeofus. The ascorbate concentration is 10 times greater in the LSD-6 and has twice the phenidone as 510-Pyro at 1:100. Maybe they intended the LSD-6 to be used at 1:1 dilution or greater.
I'm only getting a contrast index of about .25 with the 510-Pyro at 1:100 and 10min.

 

[Alan Johnson]

(there was a url link here which no longer exists)
Ascorbate regenerates pyrocatechin, it is likely it regenerates pyrogallol as well.
It may be that the rapid exhaustion of ascorbate is not due to the Fenton reaction at all but due to it being consumed by the rapidly oxidizing pyrogallol.This problem is greatly reduced with pyrocat hd as the pyrocatechin is oxidized only slowly.
Better, I should have referred not to pyrocat hd but to one of those versions of pyrocat that has vit C in it, I don't think there is an oxidation problem with that.

 

[swmcl]

Many thanks guys. It is good to hear all of your responses. Please remember that I have had a gradient of 0.47 on the same film with the same concentration for 7 mins. This should be a repeat.

The reason for being suspicious on the Ascorbic is because my Pyrocat-HD has gone for 3 years or something without me putting Nitrogen in the bottle.

TEA and glycol are used to preserve the stock solution !!

Could the pyro be oxidised ? Hmmm. Well this I do know. It is the same colour as when new. A straw colour. The little that gets around the screw part of the lid is black !

I have gone to great lengths to buy the proper product. I purchased 5 litres of TEA and various raw chemicals - a number of them at great shipping expense to Australia. I have PLENTY of some of them (like about three lifetime's supply) so I could make new batches but what is the point ?

I do also have two densitometers and an array of lab equipment to make sure of my processes. I feel confident that I am not mucking things up too much.

Pyrocat-HD does not use TEA and lasts for a long time. TEA is somewhat hydroscopic I believe but if the pyrogallol had oxidised I think the colour would be changed.

I have made up a litre batch of stock that is the ingredients of 510 Pyro but in glycol. I plan to use this with a sodium carbonate B solution. Perhaps this might eliminate a TEA involvement ?

I thank sfaber17 for his honest appraisal too. Two of us here in Australia have seen the 510 just go weak after a few months so this opinion is correlating with our experiences.

I'll look up the Ryuji formulae but I'm not inclined to rescue the thing to be honest. I never did want to embark on being my own industrial chemist ! I just saw some rave reviews about 510 and in my own complicated way tried to evaluate it. It's turning out to be a dud if only because of this lifetime issue.

Thanks for the rescue test too Rudeofus. I will try this. It'll prove whether it is the Ascorbic.

0.25 after 10 mins is stupid. It'd take a month of Sundays to get 0.6 or so !

What about a 510 brew using pyrocatechin in double the quantity in TEA ? I am led to believe that pyrocatechin isn't as active as pyrogallol that's why the doubling.

I wonder if being able to adjust the pH by using a B solution would be good too. The problem with using a single-solution developer is that the pH can't be changed without changing the whole fuel-air mixture !

Cheers guys,

Steve

 

[Rudeofus]

Steve, there are a few things you should consider:

• I have heard reports about Australian tap water, some of it has reportedly lots and lots of Iron in it. Remember, Ascorbate doesn't like Iron.
• The 510 Pyro formula doesn't properly deal with Iron.
• The developer you want to use is quite dilute, so you have little Ascorbate to begin with.

Once you have confirmed that Ascorbate decay is the culprit, you can see whether the decay happens in your concentrate or in the working solution. If a pinch of Salicylic Acid in your working solution gives you much improved results, you could try to dissolve the Salicylic Acid in your TEA concentrate.

 

[RalphLambrecht]

IIRC you need another compound to also sequester iron impurities, Ryuji Suzuki's developers use Salicylic Acid for this purpose, whereas there is no suitable compound in 510 Pyro.

@swmcl: you can test very easily whether the Ascorbic Acid in your concentrate has gone bad: prepare two standard batches of working solution, to one of which you add 0.5 g/l Ascorbic Acid and 0.5 ml/l TEA. Both compounds can be easily sourced locally. Expose two sheets and develop them one in each soup, if the second one shows normal development whereas the first one looks underdeveloped, you know the Ascorbic Acid in your concentrate has gone bad. In this case you can "repair" your developer (but not the concentrate!) until you have prepared fresh concentrate.

I had a similar problem with a Vit C developer and the addition of 1g of SalicylicAcid/liter fixed the issue for meMy contamination must have been in the sodium sulfite I used at the time.Also, I heated my distilled water in a kettle wcontaining a copper heating coil;wouldn't do that again

 

[Alan Johnson]

... you can see whether the decay happens in your concentrate or in the working solution.

Possibly by developing 120 or 35mm films in a tank where the times from the massive development chart should give good results if the concentrate has not lost activity.

 

[Rudeofus]

Possibly by developing 120 or 35mm films in a tank where the times from the massive development chart should give good results if the concentrate has not lost activity.

At the moment we have three possible routes though which Steve's developer lost activity:

1. Ascorbate decay in concentrate. The only way to work around this is by adding Ascorbate not to the concentrate, but to the working solution just before development.
2. Ascorbate decay by catalyzed aerial oxidation in working solution. This would be caused by excessive amount of Iron in water used to make working solution. An addition of 0.2 - 0.5 g/l Salicylic Acid should help in this case. Salicylic Acid can be obtained locally through pharmacies, and no, Salicylic Acid is not Aspirin (they will ask).
3. Aerial oxidation of Pyrogallol causes rapid consumption of all available Ascorbate during development. This effect would become increasingly pronounced if route #1 or #2 also plays a role. You could try to slow this effect by filling your tank with Nitrogen right after you poured in the developer. The long term solution to this issue is probably switching to a developer with less rapid aerial oxidation.

 

[swmcl]

Fellas,

1. Without reading the entire thread I'll possibly restate that I am using distilled water in the pre-wash and the developer. After development I use tap water.

2. Australian tap water is pretty damn good stuff but I concede it may have enough impurities to have an effect. The distilled water is made locally by a company and is tested at the local water testing facilities. I know the lab personally as I worked there (not in a lab capacity) for two years.

3. There is aerial oxidation occurring during development for sure. The developer has a very weak straw colour at the start and a fairly mid-strength cup-of-tea colour at the end of 7 mins.

4. I'm mixing my various solutions in those stainless milk jugs you see in the local cafe for the barista. They do come from China and they will almost certainly not be a quality stainless steel. But they do conduct heat (being metal) and they are pretty inert so I can use them in tempered water to get their temperature right.

5. If this developer reacts so badly to such tiny amounts of impurities or it just behaves badly with oxodation, then surely I am wasting my time here. It is such a shame as I now have about 3 litres of various 510 Pyro mixes !

6. I can get salicylic acid from New Directions - a beauty industry wholesaler in Sydney. I guess this might become another one of the various chemicals in my little batch.

7. I wonder what 'dealing properly with iron' means. Does it mean simply making a batch of 510 with salicylic ?

Thanks again.

I need to get out and test. Tues at the earliest I'm afraid.

 

[Rudeofus]

4. I'm mixing my various solutions in those stainless milk jugs you see in the local cafe for the barista. They do come from China and they will almost certainly not be a quality stainless steel. But they do conduct heat (being metal) and they are pretty inert so I can use them in tempered water to get their temperature right.

Ryuji Suzuki reportedly avoided stainless steel when working with Ascorbates. Since the wall thickness to area ratio of most containers is pretty small, any jug or bottle would work for heating liquids in a tempered water bath.

5. If this developer reacts so badly to such tiny amounts of impurities or it just behaves badly with oxodation, then surely I am wasting my time here. It is such a shame as I now have about 3 litres of various 510 Pyro mixes !

Of all the developers that I would want to store for long periods of time, then use in a heavily agitated roller tank, this is probably the last one on my list. If you have mixed up that much 510 Pyro, though, one could think you really like this developer, so it may be worth putting in some effort to make it work for you.

6. I can get salicylic acid from New Directions - a beauty industry wholesaler in Sydney. I guess this might become another one of the various chemicals in my little batch.

Unless you can pry a free sample from them, I'd say get a tiny amount of Salicylic Acid at first. Even if it completely solves your 510 Pyro problem, you need it in minuscule amounts.

7. I wonder what 'dealing properly with iron' means. Does it mean simply making a batch of 510 with salicylic ?

There are many complexing agents around for Iron, but by far not all of them bind Iron strongly enough to prevent the dreaded Fenton reaction which kills Ascorbate so fast. The very available EDTA wouldn't work, neither does Calgon AFAIK. The most commonly used complexing agents for this purpose are Pentetic Acid (used in Xtol) and some Phosphonic Acids (e.g. Etidronic Acid).

While it can be difficult for amateurs to source either one of the two, it is quite easy for us to obtain Salicylic Acid, which according to Ryuji Suzuki also works (as evidenced by his developers). Note, that Salicylic Acid would only solve the 510 Pyro issue if catalyzed aerial oxidation of Ascorbate in working solution is the culprit. It would not restore Ascorbate that decayed in the concentrate, and it would likely not prevent aerial oxidation of Pyrogallol.

I'd say before we propose solutions, let's pin down the source of the problem first.

 

[Gerald C Koch]

Pyrogallol is very sensitive to oxidation. In fact its main use in scientific labs is to scavenge oxygen from systems in order to provide an anaerobic environment. Developers like 510-Pyro and others like it work with stand development but as pointed out by Sandy King do not work very well with continuous agitation. There are catechol based developers that are less susceptible to oxidation but still provide a stain image.

 

[swmcl]

It is my intention to obtain some salicylic acid as a first step. That'll take another week at least. So please bear with me. I'm only going ahead with the test because the salicylic is cheap. In reality, I think my heart has given up on 510. I can't do stand development for all film types and certainly can't do it economically. So it looks as though I'll have to try a Rodinal product in a slow hand-rotated Jobo tank and the Pyrocat-HD.

Yes I know the pyrogallol oxidises quickly in a rotating tank. I only use a slow hand-rotation in all cases. The issue is that I have already 'benchmarked' this developer - or so I thought. Now I am seeing a slowing chemical reaction. Something is killing it.

I do agree with you Gerald, the catechol developers are looking good. My only complaint with Pyrocat-HD is that it is slow.

Off to wave the credit card around ...

 

[Rudeofus]

It is my intention to obtain some salicylic acid as a first step.

Try adding 1 g/l Ascorbic Acid to your working solution first. You already have it, and if this doesn't help, you won't need Salicylic Acid either.

In reality, I think my heart has given up on 510. I can't do stand development for all film types and certainly can't do it economically. So it looks as though I'll have to try a Rodinal product in a slow hand-rotated Jobo tank and the Pyrocat-HD.

I understand your frustration, but 3 liters of 510 Pyro concentrate sounds like quite an investment which I wouldn't give up yet. I promise I won't make you buy Dead Link Removed

 

[Alan Johnson]

There is a report of problems with concentrate apparently made with 85% TEA:
http://photo.net/black-and-white-photo-film-processing-forum/00crck

 

[swmcl]

Cheers Alan ...

Don't get me started with my special order from the Formulary that got to me in an already oxidized state because it was made with the wrong TEA ... It's part of the painful journey.

I have purchased the TEA from New Directions - a beauty wholesaler in Sydney - after checking it was the real-deal.

Oxidization of the pyro results in a darkening of the stock solution. Believe me, the little that gets under the cap in the threads is BLACK ... and the stock in the bottle is the same colour as it was on day one.

I am not saying 'never' but in this case I think we're looking at either the phenidone or the ascorbic or something else. I'm pretty sure it ain't the pyro.

Salicylic is on its way.

 

[swmcl]

Ummm ...

Salicylic acid does not dissolve in distilled water at 20C ...

I placed a very light powdering of the acid on top of my working solution prior to adding the stock concentrate. I put the beaker onto a magnetic stirrer for a good 5 mins ... it is just a precipitate !!

Why do I feel I am going precisely nowhere ?