Experiences with Vitamin C developers please

[swmcl]

Alan,

I do have a problem. It is real. Whatever causes the problem I don't care but I would like to stop buying a product if it is contaminated or stop using a formula if it doesn't have enough protections built in (like chelates for example)

Hey all ...

I have just read that 'ascorbic acid' can be a mixture of various mineral salts. eg. varying amounts of sodium ascorbate or calcium ascorbate to name but two. To be specific, the first sentence from Wikipedia on sodium ascorbate says, "Sodium ascorbate is one of a number of mineral salts of ascorbic acid (vitamin C)."

So maybe I should not be using 'ascorbic acid' in my mixture (nor 'Vitamin C' powder) but say pure sodium ascorbate ?? or calcium ascorbate etc ?

Perhaps those who have good experiences were unwittingly using a purer form of sodium ascorbate whereas I have a mixture of salts ?

My pyrogallol came from Bostick as did the phenidone. The TEA and ascorbic acid came from a national supplier to the health and beauty market. I think I should trust the Bostick products first.

I wonder which salt I would need if I were to buy the pure salt ? Sodium, Calcium, Potassium ?? (Is potassium ascorbate even in Vitamin C powder ?)

I reckon I might be onto something here. I need to avoid the impure 'Vitamin C' for a particular salt.

What say ye ?

 

[Gerald C Koch]

There is a difference between ascorbic acid and its various salts. Of course the human body doesn't care in what form it gets its vitamin C. So you will see sodium ascorbate and calcium ascorbate. If a formula calls for the acid form then you must use that. For high pH developers like paper developers you can substitute the sodium salt.

I have heard of vitamin C powder being adulterated with other things. One product contained 5% rose hips and was pink in color. Best to read the label. There is also another form called either isoascorbic acid or erythorbic acid. This isomer is slightly more active as a developing agent. Another source of ascorbic acid is from food suppliers as it is used as an anti-oxidant and food preservative.

 

[Alan Johnson]

Steve,
IMO there is a problem that your tests have 2 variables and it is not possible to say which is causing the lack of development, (1) The Concentrate, or (2) The aeration in your rolling tank.
I believe your Jobo 1510 tank is ,like the Paterson, just a cylinder with a spool in it.If that is so, could you develop a 35mm film in it for the time given in the massive development chart?
That should more or less eliminate aeration effects (2) . Then you can say with some certainty(3) if your result agrees with the mdc time the concentrate is OK and (4) if there is less development in the same time in your rolling tank it must be due to aeration.

 

[mrred]

Yes, 510-Pyro got trashed here. I have conversed with Jay and he has always been up front about the need to use %99 tea. Aside from the tea itself, there are no preservatives and relies on having no water polluting the developer. It is obvious this happened to the poster.

Would some salisilic acid help? Yes but the oxygen in the water would kill the phenidone as well. I think what is missed here is that 510-Pyro is a minimalist developer meant to last, under the described conditions. It does this, but sloppy techniques and poor ingredients don't help.

 

[swmcl]

May I defend myself and say that if I have made a goof up in how I've mixed things, it should be a pretty small one. Just remember that I've mixed the stock solution in TEA not water. I'm using distilled water in the pre-wash and in the working developer. I'm not sure where the thought that my stock has anything to do with water came from in post #81. Not at all sloppy here and willing to admit an ingredient with impurities is possible. I have enough common-sense and equipment to ensure a more-than-adequate process. If I can't do it then it requires a clean professional lab which is unreasonable.

The stock solution to this day looks exactly the same as it did on day 1 and is behaving exactly the same in terms of colour change by the end of the development process too. Its just that the results are weak.

All my chemicals are stored in amber glass bottles and I have a bottle of compressed nitrogen that I use to squirt into the bottles before putting a lid on. Most of the chemicals are also stored inside a fridge. I simply cannot reasonably take any more precautions.

Just to perhaps help in some way here are my pH tests.

1ml of my 99% TEA in 100ml of distilled water gives me a pH of 9.82.
1ml of propylene glycol in 100ml of distilled water gives a pH of 5.05.
1ml of sodium carbonate solution (200g per litre) in 100ml of distilled water gives a pH of 10.95.
0.5ml of same sodium carbonate solution in 100ml of distilled water gives a pH of 10.85.

Do these figures make sense ? (Especially the TEA ...)

I tried to calibrate my pH meter between tests but I've noticed it drifts with ambient temperature. If the figures look OK-ish according to theory then my process with the pH meter isn't dreadfully wrong. It only calibrates to two points not three unfortunately.

Alan, do you get the feeling I'm trying to not shoot another whole roll of FP4 ?? !! The addition of what might be a poorly constituted ascorbic did raise the CI. This could point to the ascorbic being affected in the stock or could just be showing how the addition of ascorbic helps to fend off oxidation yes ? So you are telling me that this test was inconclusive hence needing to do another FP4 roll-test. I just feel as though I would be chasing my tail. IF the developer is actually OK then my 3006 drum regime needs about 12 or 14 mins to achieve the same result as the 7 min in the 1510. Perhaps this is indeed the case but sfaber is also experiencing low CI ...

I can't recall seeing too much of a green stain even when the developer was very fresh. Could my TEA be losing its mojo and not producing a high-enough pH ? This pH reading above comes from an opened 5 litre container of 99% TEA.

What I'd really like is for a bunch of interested photographers to produce a set of curves for the Winplotter program instead of saying, "This looks great ! I've never seen such fine results ..." etc. etc. Where is even a single Winplotter curve for this developer ? The Massive Dev Chart is meaningless to me. There needs to be a database that shows all the necessary data. The dilutions, temps, CI and ISO for a start and then all of these for various times for any one film ...

Cheers,

Steve

 

[Gerald C Koch]

I can't recall seeing too much of a green stain even when the developer was very fresh. Could my TEA be losing its mojo and not producing a high-enough pH ? This pH reading above comes from an opened 5 litre container of 99% TEA.

What I'd really like is for a bunch of interested photographers to produce a set of curves for the Winplotter program instead of saying, "This looks great ! I've never seen such fine results ..." etc. etc. Where is even a single Winplotter curve for this developer ? The Massive Dev Chart is meaningless to me. There needs to be a database that shows all the necessary data. The dilutions, temps, CI and ISO for a start and then all of these for various times for any one film ...

Paragraph 1 As I mentioned before the addition of ascorbic acid to what is intended as a staining developer is curious. Typically these developers have a very low amount of preservative like sulfite or ascorbic acid. These reducing agents interfere with stain formation. TEA is not going to lose its strength.

Paragraph 2 Exactly, where are the H&D curves.

 

[Gerald C Koch]

I thought I might mention the following that anyone wanting to make 510-Pyro or other TEA or glycol based concentrates. Ignore any instruction to heat the TEA or glycol in a microwave. Doing so poses a serious fire risk. The vapors from these solvents is also toxic. (Propylene glycol is non-toxic by ingestion not by inhalation. It has also caused death when used as part of an IV fluid. So it is not as innocuous as some believe.) In addition no chemicals should be placed in any microwave used for food.

Actually the chemicals will dissolve without heating if one has a little patience. Adding the developing agents to hot TEA or glycol causes some decomposition. I have verified that this is the case as concentrates made without heating are lighter in color than those made by heating.

 

[swmcl]

Gerald,

I'm using a magnetic stirrer and heavy duty beakers to do the mixing. It takes about an hour to make the mix even at elevated temperatures.

Can I assume what you recommend is to mix at as low a temperature as possible. Thou shalt be patient !

I can confirm the colour change of the stock solution with temp too. It does go lighter as it cools.

My mixing apparatus is a Chinese cheapie so I don't know exactly what the temp would be but it says 85C and is rather hot. The thermometer is a stainless one and this might be adding some ferrous into the mix I guess...

There is a marked increase in solubility up high. As the temp goes down to 65 and below I think it might take a day or two for the various ingredients to dissolve !

I haven't been so worried about the higher temps up until this forum thread. My technique is controlled - unlike any microwave adventure. I figured my technique was OK compared to a microwave but maybe I've cooked my goose here !

Cheers,

 

[ritternathan]

If you are still having problems with the Ascorbic Acid and do want a pyrogallol/catechol dev in glycol/TEA, then mix up a small amount of 510 pyro without the AA. Then try this: in the Pyrocat series, 4g/L of AA can be replaced with 10g/L of Sod. Metabisulfite, or 13g/L of plain old sod. sulfite, so if you mix up 100ml of 510-PYRO

TEA 75 ml
Ascorbic acid 5 g
Pyrogallol 10 g
Phenidone 0.25 g
TEA to make 100 ml

leave out the 5g of AA and in the working sol. say mixed at 1:100 with a total volume of 1L, use 1.6g of sod. sulfite and see what you get. Then you can try putting in the AA, leaving all other things the same and see what happens.

 

[Alan Johnson]

IF the developer is actually OK then my 3006 drum regime needs about 12 or 14 mins to achieve the same result as the 7 min in the 1510.

Strange. Jay's rotary processor gets around 7 min for delta 100.
http://www.largeformatphotography.i...Suggestions-for-delta-100-developer-with-jobo

 

[Photo Engineer]

It is curious to me that you want densitometry of negatives produced by a staining developer. The stain will "fool" the densitometer and the readings will not be correct.

PE

 

[Gerald C Koch]

After trying the recommended mixing method using hot solvent and getting a very dark brown concentrate I concluded that a significant portion of the developing agents were being oxidized. I knew that the developing agents should dissolve fairly easily. I mixed the concentrates at room temperature. I placed all the dry ingredients in a bottle and then added the TEA and/or glycol and capped the bottle. I would shake the bottle for about a minute and then occasionally for the next hour. Never had any problems getting the organic chemicals to dissolve. However, I must admit that none of the developers tried contained any inorganic chemicals. This was done several years ago when there was a very long thread on these developers.

 

[swmcl]

Gerald,

My colours were a stronger shade of straw to a lighter shade of straw - nothing brown.

PE,

What does 'fool' mean ? I am using the required X-Rite 361T and I am pretty sure I've left it on the UV setting (I don't check it very often as I don't change it...). I am assuming the densitometer figures will read low when it is being 'fooled' ? So in the reality of enlarging, the negative will project a more contrasty image.

Even so, 'fool' wouldn't show up as a CI of 0.3 when I want 0.47 I wouldn't think. It may be a 0.40 for a 0.47 maybe is my guess.

Nathan,

I'd rather exhaust the options specific to my situation as it is rather than throw a new mix into the situation. I do hear you though. Other concoctions can be made. I'm not sure about the replacement theory though because one of the issues is to try and get a superadditive reaction between components. Maybe a new thread ...

Cheers,

 

[Photo Engineer]

You can "fool" any densitometer.

In this case, the "dye" from the developer can be a UV dye, a yellow dye or a greenish dye mixed with silver. The density is the integrated total density of the dye + silver superposed over the spectral sensitivity of the paper which is UV + blue for graded papers and is UV + blue + green for VC papers.

Unless you read the film density correctly, you can misjudge contrast and thus your ability to get a good print can be affected. I can say this, that unless you are using pure UV for exposure, then the UV setting is probably wrong. If you are using UV, then the radiation is almost invisible and your judgment of the negative in any way is useless. You cannot see the image that you are using for exposure.

PE

 

[Rudeofus]

Enlargers mostly use incandescent light bulbs as light sources, and these produce almost no UV light. So yes, the UV setting in the densitometer is probably not the ideal one for this kind of test. At the same time we have strong reason to believe that regardless of densitometer setting, swmcl's negatives are too low in contrast. Let's assume for now that the "low contrast" issue surfaced in a "damn, why do I need gradation 5 for this" way during printing, not during some "let's check the C.I. on these negs with my densitometer for the heck of it" session. By his reports I am quite convinced that swmcl's negs are low in contrast, UV or not.

We also know that Ascorbic Acid deteriorates even in its powder form, so there is good reason to believe that it will also slowly deteriorate in TEA. He then added Salicylic Acid and found little improvement. Addition of Ascorbic Acid did some good, but was certainly not the big break through we might have expected, therefore I think that pH is the culprit. Why would his pH be off? Two reasons come to my mind:

1. As Ascorbic Acid deteriorates, it decomposes into acidic compounds. This will be the case both while in the concentrate, and in the final developer working solution.
2. TEA in aqueous solution will readily absorb CO2, lowering its pH just like CO2 lowers the pH of NaOH.

In his article about 510 Pyro, Jay de Fehr writes that Pyro is active mostly at pH 10. This developer recipe, as mixed by swmcl, starts with TEA at pH 9.82 which is then lowered by addition of Ascorbic Acid and Pyrogallol, so it's borderline active to begin with. Any of the above listed scenarios will lower pH to the point where this developer will no longer give normal development. BTW, in the same article Jay also writes why replacing Pyrogallol with Catechol in this recipe won't work.

Assuming swmcl still has the source ingredients for 510 Pyro, I recommend he does the following four measurements:

• Mix a single run batch of fresh 510 Pyro working solution from raw ingredients, measure its pH.
• Run this batch in your rotary processor for seven minutes, the recheck pH. You don't have to put film into the tank for this test.
• Repeat the above two measurements with a batch of working solution mixed from your aged concentrate.

My prediction is that both batches will see a drop in pH, and that the batch mixed from aged concentrate will be lower in pH to begin with. If this prediction is confirmed, check how much Sodium Carbonate you need to add to developer mixed from aged concentrate to bring pH back to where it should be, and check whether you suddenly get normal contrast with this new batch.

 

[Photo Engineer]

You will note that Jay is no longer a member of APUG. IDK what transpired but there was great controversy over his findings here and on PN. I can't comment any further on this but I do suggest that you exercise caution. I found him to be a reasonable reporter, but based on other evidence, I may be wrong.

PE

 

[Gerald C Koch]

I went back to to Jay's original article and found the following interesting information

Dilution: 1+100

Starting point development time: 5-7 mins.

Notes: Can also be diluted up to 1:500 for EDRA (extended development/reduced agitation) techniques, with one minute initial agitation, followed by one inversion every 10-15 minutes for one hour, or so.

This specifically rules out using a dilution higher that 1+100 with any form of continuous agitation.

I have also been doing a bit of research into pyrogallol and several mention its lack of reliability. A typical entry is "Pyrogallol was the most popular developing agent of the early 20th century. However its popularity declined dramatically as newer developing agents became available. The decline was also furthered by pyrogallol's reputation as an erratic and unpredictable performer." This contrasts nicely with the increase in popularity of catechol based developers at about the same time.

 

[nworth]

As you can see from the discussion, there are a lot of subtleties to ascorbic acid developers. But it isn't as bad as all this seems to make it. The Fenton reaction can be avoided with reasonable care - even just using distilled water will usually work, and the better developers use chelating agents to avoid the problem. I have tried a number of ascorbic acid developers, and they have ranged from absolutely terrible to very good. The absolutely terrible ones were usually simple, relatively untested formulations found here and in magazines. The well tested, well established ones were generally pretty good. But I have seen no advantage to these developers, and I generally prefer the images from more traditional developers. One of the reasons for their popularity has been the environmental advantage of Vitamin C over hydroquinone, but it is marginal at best.

 

[sfaber17]

Maybe we are thinking wrong about the Fenton reaction. What if the dissolved oxygen is the main factor that is affecting the pyrogallol, and the recipe depends on the ascorbic acid in conjunction with the Fenton catalysts to take out the dissolved oxygen before use. If we use too pure ingredients, then it may take too long after mixing to get out the dissolved oxygen. Nathan's post got me wondering. How did you figure the quantities in that post?

 

[mrred]

Not living an an area where I can get hydroquineone easily, I use ascorbic acid all the time. It is second nature to use tea and sal acid in every developer I make, But it is also a habit to only make what I need; it can't go bad if it is not hanging around. The other perk is there is a factory close to me that makes the food grade ascorbic acid, so it's always fresh.

 

[sfaber17]

Thanks to Rudeofus for that pointer to Jay's writeup. Good idea to check into the pH. Some key points I noticed was that pyro is sensitive to the pyro/sulfite ratio, hence we can't just dump in sulfite to try and get rid of oxygen. The ascorbate/phenidone is a known superadditive combo, so it seems that it would be important to maintain some amount of ascorbate. Not sure how much the ratio of those affects things. Looks like the spectral differences of the pyro stain will affect the contrast printed on vc papers, so we may get different results on the prints than we expect from measured CIs.

 

[Rudeofus]

Some key points I noticed was that pyro is sensitive to the pyro/sulfite ratio, hence we can't just dump in sulfite to try and get rid of oxygen.

With excess sulfite you won't affect pyro or its developing properties, but you will quickly remove oxidized pyro which many want to keep for its staining property. You will need to scavenge some of the oxidized pyro, though, because aerial oxygen will create oxidized pyro absent any development reaction.

The idea behind 510 Pyro, as described by Jay de Fehr, was to use Ascorbic Acid instead of Sulfite for the same purpose, because it restores oxidized Pyro AND is soluble in TEA, thereby allowing you to make a single concentrate.

The ascorbate/phenidone is a known superadditive combo, so it seems that it would be important to maintain some amount of ascorbate.

The Phenidone/Ascorbate combo in 510 Pyro is not overly active, because there is very little Ascorbate in 510 Pyro working solution. Look at this and this curve from Pat Gainer's article on Phenidone/Ascorbate superadditivity: at 0.5 g/l Ascorbate I wouldn't expect much overall development.

This argument actually confirms my recent theory that Ascorbate depletion the main culprit (except for the fact that AA's decomposition products lower pH): with no Ascorbate left in working solution he should get high base fog rather than low contrast.

 

[sepiareverb]

Somewhat off topic, but I just got a receipt at a local store that was printed using a vitamin C based developer.

 

[sfaber17]

With excess sulfite you won't affect pyro or its developing properties, but you will quickly remove oxidized pyro which many want to keep for its staining property. You will need to scavenge some of the oxidized pyro, though, because aerial oxygen will create oxidized pyro absent any development reaction.

The idea behind 510 Pyro, as described by Jay de Fehr, was to use Ascorbic Acid instead of Sulfite for the same purpose, because it restores oxidized Pyro AND is soluble in TEA, thereby allowing you to make a single concentrate.

I don't see where he explicitly states that AA restores oxidized Pyro. Do you know that to be a fact, or
could it be that the AA just protects Pyro against oxygen?

The Phenidone/Ascorbate combo in 510 Pyro is not overly active, because there is very little Ascorbate in 510 Pyro working solution. Look at this and this curve from Pat Gainer's article on Phenidone/Ascorbate superadditivity: at 0.5 g/l Ascorbate I wouldn't expect much overall development.

This is on the steep part of the CI vs AA concentration curve, so if the developer is dependent on some
contribution there even though it is low, it may be sensitive to loss of AA. The Gainer article goes on to
say how much a little bit of oxygen can take out a lot of AA, and sulfite can't protect AA from oxygen.

This seems like a tight balancing act that may vary with dissolved oxygen.

 

[Rudeofus]

I don't see where he explicitly states that AA restores oxidized Pyro. Do you know that to be a fact, or
could it be that the AA just protects Pyro against oxygen?

Here are my reasons why I think that AA restores oxidized Pyro:

1. I have reason to believe that AA is the stronger reducer of the two. "The Theory of the Photographic Process, 4th Edition" by T.H. James does not provide a direct comparison of AA against Pyro, but it lists Pyro as similar in reduction potential as HQ (page 305), then shows the reduction potential vs. pH curves of HQ (page 305) and of AA (page 307).
2. IIRC, oxidation of HQ and derivatives thereof is initially reversible unless the oxidized developer is somehow scavenged. It should therefore be possible for AA to act on oxidized Pyrogallol, especially if there is no scavenger for oxidized Pyro around (usually Sulfite).
3. Rollo Pyro is optimized for rotary processing and uses the same amount of Pyro but twice the Ascorbic, and there are claims that it doesn't stain much in tray processing. It looks like both devs start as PC couple until AA runs low, at which point Phenidone/Pyro take over.

If people can point to better literature or have telling test results, I'd love to hear from them.

This is on the steep part of the CI vs AA concentration curve, so if the developer is dependent on some
contribution there even though it is low, it may be sensitive to loss of AA. The Gainer article goes on to
say how much a little bit of oxygen can take out a lot of AA, and sulfite can't protect AA from oxygen.

This seems like a tight balancing act that may vary with dissolved oxygen.

There isn't that much Oxygen dissolved in water at room temperature. Also, the fact remains that swmcl didn't see much improvement when he added Salicylic Acid and Ascorbic Acid. The effect of AA on development in 510 Pyro must be minor IMHO. Since swmcl is very well setup with pH meter and densitometer, I hope he can soon confirm my theory about pH drop causing his loss of contrast and film speed.