Halcyon p-phenylenediamine developer test

[Alan Johnson]

Opinion is divided over PPD, some say it has unique properties, others that it was replaced by Microdol (now discontinued) and by Perceptol (still available) as an ultrafine grain developer.(See the Film Developing Cookbook by Anchell and Troop for more details)
PPD can cause permanent allergy in some cases and appropriate care in handling is needed, see FDC or Darkroom Cookbook.

Here I tested the ascorbate version formulated by Jay DeFehr:
https://www.largeformatphotography....?71010-Halcyon-superfine-grain-film-developer

I used it without replenisher, starting at 9min 70F for the first film and increasing time by 5% for each subsequent roll as suggested in FDC. I found it to give about half box speed (sun/shade, average metering) to 1/3 stop less than box speed (Dull, average metering).Of course, this is only a very limited test.
Very fine grain results were obtained cf Xtol and Pyrocat (attachments).
IDK how it compares with Perceptol or with the older PPD based developers or how it works.

 

[chriscrawfordphoto]

Interesting. The Film Developing Cookbook claims that PPD destroys image sharpness, but in your examples the PPD developer has not only finer grain but also MUCH better fine-detail resolution!

Have you shot any real-world photographs with it? I'm curious how the tonality is.

 

[Alan Johnson]

I put this on the Analog section as it may also be of interest to darkroom printers but the only results I have with it so far are on my Flickr, not darkroom prints.
All the attachments are sharpened equally, IDK if this higher resolution with Halcyon is an artifact of sharpening or some chemical effect with ascorbate.

 

[sedwards]

Would be interesting to see a comparison between Halcyon and something like Perceptol.

 

[Alan Johnson]

It's on my "to do" list one day.

 

[koraks]

This is interesting. I wonder if the ppd could be replaced with e.g. CD3 (in a higher concentration). I don't have any ppd lying around, but substantial heaps of CD3 and CD4...
I'd have to run to a drugstore to get some aspirin as well.

 

[Anon Ymous]

...
I'd have to run to a drugstore to get some aspirin as well.

Not quite. Aspirin is acetylsalicylic acid, but the formula calls for salicylic acid. That said, a drugstore is a likely source of salicylic acid.

 

[koraks]

Good catch.
I understand that its function in this formula is that of an antifoggant, as ppd-based developers apparently suffer from giving dichroic fog with longer development times. Would replacing it with, say, benzotriazole likely achieve the same thing?

 

[Alan Johnson]

Good catch.
I understand that its function in this formula is that of an antifoggant, as ppd-based developers apparently suffer from giving dichroic fog with longer development times. Would replacing it with, say, benzotriazole likely achieve the same thing?

I believe its function ( and that of TEA in the replenisher not used by me) is to chelate iron and copper ions and prevent them from catalyzing the oxidation of ascorbate , Jay DeFehr probably got the idea from Ryuji Suzuki (DS-10, DS-12).

 

[koraks]

In that case I suppose a small amount of edta could be substituted, eg 1 g/l?

 

[Alan Johnson]

I wonder if the ppd could be replaced with e.g. CD3 (in a higher concentration). I don't have any ppd lying around, .

My efforts to do this with CD-4 were a failure, I think that PPD has a stronger solvent action(it is also a weak developer).
https://www.photrio.com/forum/threads/replace-ppd-by-cd-3.68079/

 

[Anon Ymous]

In that case I suppose a small amount of edta could be substituted, eg 1 g/l?

No, it's not effective in this role. Ideally, DTPA-5Na is what you would use, just like in Xtol, but salicylic acid is another option, although not as good AFAIK. Salicylic acid on the other hand is far more easily obtainable.

 

[bnxvs]

In that case I suppose a small amount of edta could be substituted, eg 1 g/l?

I recommend reading this article https://www.sciencedirect.com/science/article/pii/S0273230018301752.
EDTA and DTPA are, in principle, fairly related chelating agents. They differ only in particulars. The article contains data on activity with different metal ions in various pH. So, it seems to me that such a replacement is quite acceptable.

p.s. You can also try to use Sintron B (Tetrasodium EDTA) as an alternative to Pentasodium DTPA. But you'll need to adjust pH.

100ml water
24g NaOH
100g EDTA

 

[Alan Johnson]

https://web.archive.org/web/2007010...grain.org/wiki/index.php/Ascorbate_Developers
Here is Ryuji on the subject, appears that he considered that chelation alone was not enough, the salycylic acid also better deactivates iron as a catalyst.
I don't know enough to comment.

 

[koraks]

From this, I deduce that if no long lifetime is required (eg one shot mixing) and distilled water is used, the chelating agent may be omitted - although it would have to be tested. An alternative approach would be to replace the ascorbate/asgorbic acid with eg hydroquinone, although thid may affect grain and I'm not sure it'll be sufficiently active at this relatively low pH (?)
However, since I don't have any ppd or cd2 and I'm not really prepared to get either for this experiment, I think I'll let it rest for a bit.

 

[Anon Ymous]

FWIW, Crawley suggested using his FX-55 developer within 36 hours once mixed. Ascorbic acid based developers can die unexpectedly, but not instantly. In my experience, shelf life can be very good, even if no DTPA, or salicylic acid is used, but it's certainly not guaranteed. I've mixed a modified version of the Xtol patent formula and the solution worked fine after 6 months, but in completely full plastic bottle.

 

[Rudeofus]

I recommend reading this article https://www.sciencedirect.com/science/article/pii/S0273230018301752.
EDTA and DTPA are, in principle, fairly related chelating agents. They differ only in particulars. The article contains data on activity with different metal ions in various pH. So, it seems to me that such a replacement is quite acceptable.

I recommend you take a look at this article: https://www.sciencedirect.com/science/article/abs/pii/S0003269702003226
It describes in detail, that EDTA does not prevent Fenton reaction from occurring, and it shows graphs, how quickly this reaction can destroy Ascorbic Acid in solution. In the experimental setup there is 10% deterioration of Ascorbate alone, over 50% deterioration of Ascorbate in the presence of EDTA, and less than 5% deterioration of Ascorbate in the presence of DTPA, all measured within 45 minutes after mixing.

There's another article to be found under https://www.tandfonline.com/doi/abs/10.3109/10715768609051638
It also describes the effect of different chelating agents on deterioration of Ascorbate. Again, this deterioration happens within less than an hour. It is strongly dependent on the amount of Iron present in solution. For our purposes, this Iron amount depends on both water quality, and the purity of other ingredients used to mix our liquids. We can use deionized water to mix our soups, but typically have little control over ingredient purity.

Things may be a little bit better in practice, because we typically use more than the 50µmol/l of our chelating agents, but I'd rather not assume it's going to take days until Ascorbate deterioration becomes a thing, unless you use proven and powerful sequestering agents like DTPA or phosphonic acids.

 

[bnxvs]

I recommend you take a look at this article: https://www.sciencedirect.com/science/article/abs/pii/S0003269702003226
It describes in detail, that EDTA does not prevent Fenton reaction from occurring, and it shows graphs, how quickly this reaction can destroy Ascorbic Acid in solution. In the experimental setup there is 10% deterioration of Ascorbate alone, over 50% deterioration of Ascorbate in the presence of EDTA, and less than 5% deterioration of Ascorbate in the presence of DTPA, all measured within 45 minutes after mixing.

Thanks for the links. Unfortunately, I'm not ready to buy access to these articles for purely informative purposes)))
It's quite possible that the compatibility of various chelates with ascorbate is different. Therefore, I usually prefer disposable solutions or glycol based concentrate (when it's possible).

p.s. I found the text of the article (thanks dE fENDER). This is very surprising and discouraging information for me. Thanks again for the links!

 

[Rudeofus]

It's quite possible that the compatibility of various chelates with ascorbate is different.

This is not about compatibility between ascorbate and some chelating agents. Different chelating agents bind Iron to different extent, and there is a difference between FeII and FeIII, expressed by their logarithmic stability constants:

• FeII and EDTA: 14.33
• FeIII and EDTA: 25.10
• FeII and DTPA: 16.55
• FeIII and DTPA: 28.60

This shows, that the binding between Iron and DTPA is much tighter than between Iron and EDTA. This is especially significant at neutral to alkaline pH, where Fe(OH)2,3 is likely to form:

 

[Alan Johnson]

https://web.archive.org/web/2007010...grain.org/wiki/index.php/Ascorbate_Developers
It's not clear if DTPA, (used btw in Xtol) is better than salicylate.
DTPA complexes iron but does not inhibit its redox catalysis, the salicylate complex is inactive as a catalyst.(see link).

 

[Rudeofus]

It's not clear if DTPA, (used btw in Xtol) is better than salicylate.
DTPA complexes iron but does not inhibit its redox catalysis, the salicylate complex is inactive as a catalyst.(see link).

It is quite clear, that DTPA works, because XTol is still a thing. If XTol has a working solution shelf life of 6 months, and that's Kodak's conservative estimate, then redox catalysis is effectively inhibited. Yes, there were folks with extra hard water, who could overwhelm the DTPA in XTol, but those were a tiny minority. The combination of Salicylate and Triethanolamine may also work, but for some reason these never found their way into a long term commercial product.

 

[Anon Ymous]

@Rudeofus Let's assume that the salicylic acid - triethanolamine combination works just as well as DTPA. Triethanolamine is a liquid, so the end product would also be a liquid. But this also means that the timer for the product's life starts ticking by the time it is produced, not mixed by the end user like in Xtol's case. This can mean that by the time somebody buys the developer, it could be dead.

 

[Rudeofus]

People have been desperate for liquid ascorbate developers concentrates, so the liquid state of TEA would rather help than be a hindrance. The biggest obstacle seems to be, that neither Salicylic Acid, not TEA really solve the problem of Ascorbate stability, at least not in aqueous solution (c.f. PC-TEA).

 

[Alan Johnson]

Here are the results for Halcyon, Perceptol and D-76. All are sharpened equally.
Lppm resolution is subject to small scanning height errors.

Halcyon appears to be the clear winner for fine grain, in agreement with old timers who considered PPD the finest grain developer.

Halcyon has some downsides (1) May cause allergy, see eg The Film Developing Cookbook 2020 p87. (2) Deposits silver particles and requires frequent filtering of the stock solution. (3) Speed loss cf D-76, lower density.(4) Stains (5) Hard to find ingredients.

 

[Alan Johnson]

I tried Halcyon as a 2-bath developer to try to get a bit more speed out of it.
It was tested using Rollei Retro 400s, believed based on Aviphot 200, because I happened to be using it at the time.
What follows gave an increase of about 1/3 stop in shadow speed cf Halcyon alone(comparing negatives of the same sky density).
There was slightly better separation of clouds and sky.
Also a slight increase in grain.
All attributed to reduction of development in Part 1 (Halcyon) and preferential development of the shadows in Part 2.

Part 1 (Halcyon)
PPD.....................7g
Sodium Sulfite.....50g
Salicylic acid........0.5g
Ascorbic Acid.......3.5g
Water to................1L..................pH ~8
Part 2
Sodium Carbonate anh...30g
Sodium Sulfite.................35g
Water to...........................1L.......pH ~11

I developed Rollei Retro 400s for 90% of the time in Halcyon (Re-used time see post 1) in Part 1
Followed by 8m 20C in Part 2, agitate 2 inversions every 2 min.
The effective EI was increased from 100 to 125.

Conclusion - Not a magic bullet ultrafine grain developer, Halcyon always loses speed cf D-76.