Anti-fogging agent to replace benzotriazole?

I'm working on a... unique formula for an environmentally friendly ascorbic-acid only developer. Basically something really designed so that you could mix it with things mostly from around the house. Current ingredients:

* ascorbic acid
* sodium oxalate (potentially optional, chelating agent, should help shelf-life and seems to prevent the pH shift that ascorbic acid radicals have. May regenerate ascorbic acid like sulfite does with other developing agents -- can also be substituted with easier sourced oxalic acid and appropriate amount of hydroxide)
* sodium carbonate (to make a buffer)
* sodium hydroxide (pH is ~12.5)
* potassium bromide (seems possible to replace with sodium chloride in the future to make it more "household")

However, I always get dingy borders unless I add benzotriazole. The developer is extremely eco-friendly aside from that addition. It also produces very nice distinctly cold tone results with very deep blacks and seems to last a few hours once the alkali is added. However, without the benzotriazole I always get dingy borders with either warm orange fogging with just a little bromide added, or more subtle grey fogging with a surplus of bromide.

Is there any eco-friendly and preferably "household" ingredient that can be used here? I've observed that oxalate can in some cases behave like a very weak anti-foggant, but not to the extent needed without a very large amount, an amount requiring the higher solubility of potassium oxalate which is a lot harder to source and of course more expensive. I plan on keeping the final solution in 2 parts, the ascorbic acid is kept naturally acidic which seems to keep on the shelf significantly better. I've also tried using lower alkalinity, but all tests thus far toward that were not good (10m+ dev time and with weak blacks).

And before someone says it, yes, I know I could add a smidge of phenidone and probably have something that works great at lower alkalinity and with less fogging tendency. I'm just trying this for purely experimental and creative purposes and because I've never seen a suitable ascorbic acid only print developer. The results are also very nice and somewhat variable contrast/exposure due to how shadows develop. Definitely colder tones than I've seen from pretty much any cold tone developer I've tried, with or without the benzotriazole. Example print attached (Ilford MGIV portfolio postcard paper)

I consider DS14 "eco friendly enough". Amount of phenidone/dimezone is very small there and it is not so harmful substance. Sodium oxalate is toxic to humans as well...

A while back I printed with "Beerenol", which was a crazy concoction made from beer, Ascorbic Acid and lots of Sodium Carbonate. The beer made it reek to high heaven, but the soup developed substantially faster with the beer than without it.

Stanislav Boščík said:

I consider DS14 "eco friendly enough". Amount of phenidone/dimezone is very small there and it is not so harmful substance. Sodium oxalate is toxic to humans as well...

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Phenidone is considered "extremely harmful to aquatic life", though I don't carry that warning with much care due to the tiny amounts used for a superadditive developer. It's hard to determine how toxic oxalate actually is to humans. It's known that if you eat it, then it basically is very likely to cause kidney stones, but otherwise is a fairly natural thing to exist in nature. Many things create oxalic acid as part of living and sodium oxalate is just neutralized oxalic acid by a sodium salt (ie, hydroxide, carbonate). There's also no warnings in the MSDS about aquatic life. There are some warnings about both swallowing and skin contact being dangerous, as a category 4 danger (LD50 2g/kg), but there's not really much I can find on skin contact. And I'm pretty sure even sodium chloride is considered around that dangerous for swallowing, and is rated as an irritant for skin contact. Basically it's really hard to determine how actually dangerous oxalate is. I can't find any real research papers about the effects of anything other than direct ingestion (ie, not skin contact) and the MSDS sheets are so careful to be extremely cautious that even baking soda has recommendations for do not dispose of in sewage, wear goggles, gloves, PPE... etc. If you can find me something pointing oxalate as something directly dangerous I'd definitely appreciate it.

Rudeofus said:

A while back I printed with "Beerenol", which was a crazy concoction made from beer, Ascorbic Acid and lots of Sodium Carbonate. The beer made it reek to high heaven, but the soup developed substantially faster with the beer than without it.

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I've considered trying to use coffee or tea for that superadditive bit, but I've never seen them used successfully on paper and capable of developing a proper black, plus with coffee/tea you still have tannins that will stain the paper.


I'm not exactly opposed to using benzotriazole for the nice results, but more struck by the curiosity of just trying to make something without anything exotic that you'd normally have to order from a chemical supplier (ie, phenidone, hydroquinone, metol, etc)

When bromide was introduced to photographic developers, it was a standard compound sold in pharmacies to treat certain conditions. So back then it was pretty close to what you look for, "something from around the house", definitely not exotic. I can still buy it from any of my local pharmacies, as long as I tell them what I want to use it for.

As far as other restrainers are concerned: I did look through the list of inorganic silver salts, and the vast majority is poorly soluble, but not nearly as insoluble as silver bromide. The most notable exceptions are, of course, Silver Iodide and Silver Sulfide. There is a long list of organic molecules, which form insoluble silver salts, but these are not compounds you would easily find in your kitchen. Some of these organic compounds are used to prevent corrosion of copper and silver, maybe you can find something useful in that range of commercial products.

That was what I was looking through but ultimately just decided it was impossible. In tests it required massive amounts of benzotriazole and bromide to completely prevent fog across a range of papers... and then the results were abysmally slow. One interesting workaround is that you can over expose and not develop to completion (blacks will completely darken long before highlights are there) to avoid the fog, but it’s basically all the pains of lith printing with none of the benefits at that point, though it does allow for some interesting amount of contrast control.

regardless, I’ve decided to use my remaining “part A” developer stock in formulating a more typical phenidone-ascorbic print developer, which has been extremely successful. I’m letting the tray sit out overnight, but thus far it has lasted 5 hours with no change in activity and only a very minor change in overall tone (shadows slightly more open when aged). The solution is a pale distinct pinkish orange color however where it started out as clear. It is otherwise a neutral tone, slightly elevated shadow contrast, and very fast print developer that is complete within 1 minute for RC papers and 2m for FB paper, even after 5 hours of sitting in an open tray

https://web.archive.org/web/2007010...wiki/index.php/Print_Developer_Recommendation
Here is DS-14 which is of similar type.
TEA and Salicylic acid are chelating agents , they will extend tray life somewhat but are not essential.

Alan Johnson said:

https://web.archive.org/web/2007010...wiki/index.php/Print_Developer_Recommendation
Here is DS-14 which is of similar type.
TEA and Salicylic acid are chelating agents , they will extend tray life somewhat but are not essential.

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I’ve found oxalate to be a “one stop” chelating agent to replace the TEA and salicylic acid, which is also very easily available if made in solution from oxalic acid and hydroxide. Otherwise my formula is similar with less bromide and using phenidone (can’t find a reliable source of dimezone) and no sulfite at all. Nearly on the 12 hour mark with no hint of the developer dying other than the solution growing more pink/orange and no change in tonality of results compared to when it was 2 hours old

Phenidone slowly hydrolyzes in alkaline solution. This makes Phenidone utterly unsuitable for liquid concentrates, but absolutely no problem to use in freshly mixed liquids. Since your current time horizon for your developer is dozens of hours, not weeks, Phenidone will work well.

BTW: since developer speed seems to be an issue, you should seriously consider adding Sodium Sulfite to your soup. Solvents to speed up developer action.

Rudeofus said:

Phenidone slowly hydrolyzes in alkaline solution. This makes Phenidone utterly unsuitable for liquid concentrates, but absolutely no problem to use in freshly mixed liquids. Since your current time horizon for your developer is dozens of hours, not weeks, Phenidone will work well.

BTW: since developer speed seems to be an issue, you should seriously consider adding Sodium Sulfite to your soup. Solvents to speed up developer action.

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Although it'd be nice to have a single super stable stock solution developer like DS-14/15, dimezone seems to be a lot harder to get than phenidone (along with more expensive and less stable as a powder) and is utterly unsuitable for such a plan. However, if I can get 24+ hours of stable tray life out of a very stable 2 part solution mixed with tap water, then that's good enough for me. Thus far I'm at ~28 hours and it has discolored to a very vibrant pinkish red color, but still develops to give about the same results within 1 minute with RC paper. Keeping the ascorbic acid at an acidic pH and with oxalate in the solution has been shown by one study to dramatically increase the stability of the ascorbic acid, not to mention the ideal chelating properties of oxalate. Also, despite oxalate being known by the MSDS as somewhat dangerous, it is a very natural part of the environment (basically many things create oxalic acid, and when it's neutralized oxalates are made), and in the small amounts used, there should be no risk of even an accidental glug killing you, the high pH would be more harmful than anything (pH ~11).

I decided to forego adding sulfite because in testing it didn't seem to have any real affect on the speed or tone of development with a pure AA developer. In fact, it actually seemed to slow down development. I also haven't added it to the phenidone-AA developer because it's been shown that sulfite is a very poor preservative of both components, and in the case of AA may even accelerate oxidation. I've tried adding alternative silver solvents such as thiocyanate, triethanolamine, and sodium chloride, but none of them made a real difference for the AA only developer and the very fast speed of phenidone-AA means it is not necessary. I'm basically building something that should work a bit faster than DS-14 and is suitable for use with phenidone and using tap water for mixing, and without the triethanolamine as it can be somewhat difficult to get in some regions.

Now I really miss PE...

Andrew O'Neill said:

Now I really miss PE...

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Yes, I thought of that as well when posting this. He's commented quite extensively about ascorbic acid in the past. Truly a great amount of knowledge, and a genuinely nice guy, has been lost.

Regardless, the oxalate+ascorbic acid paper has been found: https://onlinelibrary.wiley.com/doi/abs/10.1002/recl.19450641004 (cough sci-hub cough)

Dimezone-S in the US is listed by Photoformulary. In the UK and Europe it is probably still available from Moersch, they got me some a couple of years back although it is not listed.
So your formula could probably be made up as a stock solution.

Alan Johnson said:

Dimezone-S in the US is listed by Photoformulary. In the UK and Europe it is probably still available from Moersch, they got me some a couple of years back although it is not listed.
So your formula could probably be made up as a stock solution.

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Photographers formulary lists it but is out of stock of all sizes. Only immediate source I’ve found yi by it is ebay (don’t trust purity and freshness) and Adorama (expensive)

edit: my primary point being that it is hard to come by, especially outside of the US. So, I’d rather formulate with the much easier to get ahold of (and much cheaper) phenidone A

Alan Johnson said:

In the UK and Europe it is probably still available from Moersch, they got me some a couple of years back although it is not listed.
So your formula could probably be made up as a stock solution.

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Fototechnik Suvatlar sells Dimezone-S under its correct chemical name "Hydroxylmethyl-methyl-phenidon", it's in the price list.

https://web.archive.org/web/2007011...lvergrain.org/wiki/images/2/2d/Pat3658527.pdf
Oxalate has two -COOH groups, it is similar to compounds mentioned on p2 of this patent.

earlz said:

Yes, I thought of that as well when posting this. He's commented quite extensively about ascorbic acid in the past. Truly a great amount of knowledge, and a genuinely nice guy, has been lost.

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Did he pass away?

Trey said:

Did he pass away?

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Yes.

There is an ongoing thread on this site.

Terry S

earlz said:

......, dimezone seems to be a lot harder to get than phenidone (along with more expensive and less stable as a powder) and is utterly unsuitable for such a plan........

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Is Dimezone less stable as a dry powder than phenidone? What about Dimezone-S? I ask because I've some Dimezome-S that hasn't been used for years, and I'm planning to get back into the darkroom.

john_s said:

Is Dimezone less stable as a dry powder than phenidone? What about Dimezone-S? I ask because I've some Dimezome-S that hasn't been used for years, and I'm planning to get back into the darkroom.

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No, powder stability is almost same for all phenidones (i'm using bottle from 1960-th), but Dimezone is less soluble and Dimezone-S is ok on that point.

IIRC Dimezone-S lasts longer in solution than Phenidone. I keep it mixed in Propylene Glycol. I've had a bottle of it for probably 8 years now and it is still good.