Synthesis of Rodinal Substitute (looking for help with the chemistry)

[Ian Grant]

Well typical Kodak fixers used 15 g/litre Potassium Alum as hardener, so that gives us a basic Potassium level that's not an issue and carry over as long as there's a stop/wash is hardly going to increase it significantly.

I've looked at some of my German books but can't see Potassium compounds used in between developer and fixer, but it's possible some used a Potassium Alum hardener before fixing. We forget that it's not so many years ago when all films had much poorer hardening and people used hardening stop baths. FP3 and HP3 and the then generation of similar Kodak films would reticulate with only a few degrees temperature variation and pre WWII films were even softer so various stop bath hardeners were advocated.

Ian

 

[Rudeofus]

I've looked at some of my German books but can't see Potassium compounds used in between developer and fixer, but it's possible some used a Potassium Alum hardener before fixing.

Well, there's the Agfa 304 fixer formula which I already mentioned and which has been recently discussed here in a separate thread. I also have a formula book from a guy called "Udu Raffay", which was sold through Suvatlar, it contains a universal color BLIX formula also with Potassium Sulfite instead of its Sodium equivalent. Evidently neither recipe's author thought, that Potassium ion would poison fixer.

 

[Photo Engineer]

Both Frank and Schramm cite Potassium Thiosulfate as being virtually ineffective as a fixing agent due to the low solubility of their Silver complexes. (Haist, VI, P 566). Mees, in the revised edition of his book "Theory of the Photographic Process" illustrates the effect of using Potassium Thiosulfate vs Ammonium and Sodium salts. At 10% (100 g/l), the Potassium salt won't fix.

There is no question that Potassium slows fixing or halts it. It therefore remains to be seen what happens in mixtures and in amounts carried in from the developer and stop. I use Potassium salts in developers myself, but carefully monitor the activity of my fix.

Hardening fixers are slower than other fixers. It is a matter of debate as to how much of this slowdown ins caused by the hardening action and how much by the Potassium itself.

I bring it up to urge caution and testing of your fix and wash for efficiency if Potassium is used in your process.

PE

 

[Ian Grant]

Lets be straight talking and completely honest here, Potassium salts at high levels are used in a great many commercial developers and some fixers, there is no need for any caution, they don't cause issues at the levels used in practice. If there was an issue then Kodak Ilford, Agfa (well their successors now), etc wouldn't use them and we wouldn't have most of the liquid developers available today.

The potential issue is so small that Kodak and Fuji (and others) don't (or didn't) include a stop bath or water rinse on many of their B&W processing machines between developing and fixing, details of this can be found in a thread about Stop baths and alternatively a water rinse.

So bearing in mind that Ilford have been selling concentrated PQ developers, with high levels of Potassium, like PQ Universal, and later variations like Multigrade Developer, Warmtone developer etc, for over over 60 it's interesting that this issue should suddenly spring up in this thread. Also bear in mind that Kodak Dektol (liquid - Polymax in some markets) and Kodaks developers used in machine processors doing straight from developer to fixer have an equally high Potassium level.

Lets not build up yet another false myth. There's no doubt that higher levels of Potassium might cause problems but our usage is way way below that threshold,

Ian

 

[John Bragg]

there was an appugger here a few years ago who
had a different recipe for rodinal, and he suggested
you need to use extreme heat to combine some of the ingredients
i don't remember the guy's name, his avatar ken or something
his avatar was a monkey wearing glasses i think. maybe his
old posts canhelp you
good luck

Was it Zorkikat ? He was/is Philipines based. He successfully made Par-Rodinal due to supply issues in Philipines.

 

[sfaber17]

It all has to do with the relative sizes of the sodium and potassium ions. Another factor is just how much of the negative nuclear charge is seen by a valence shell electron. The presence of an extra electron shell in potassium ions reduces the nucleus electron attraction. All in all increased solubility with potassium salts over sodium ones. That is why Agfa chose using concentrated solutions of potassium hydroxide and sulfite over sodium solutions.

What about Li salts? They are soluble and deliquescent. Maybe there is a balance between less lattice attraction with greater size and greater energy released with hydration of the smaller sized ions, so it isn't always clear.
I think potassium nitrate vs sodium nitrate is another counter example.

 

[Ian Grant]

Historically the potassium carryover issue (if there is one) seems to have had at least something to do with the use of stop baths based on potassium compounds. Apparently these (and the use of potassium compounds in general) were popular in pre-WWII Germany, at least in part for cost reasons, and subsequent research revealed potential problems. At least that's the story.

Rudeofus mentions Agfa 304 rapid fixer which is

Sodium Thiosulphate . . . . . 200g
Ammonium Chloride . . . . . . 50 g
Potassium Metabisulphite . . 20g
Water to 1 litre

That's a about 14% Potassium ions compared to the Sodium & Ammonium, other Agfa fixer formula state either Sodium or Potassium Metabisulphite and with Agfa 301 that goes up to around 22% when Potassium Metabisulphite is used, it's excatly the same with Kodak F.52 fixer.

While I made up Agfa 304 fixer I substituted Sodium Metabisulphite as that's all I keep on my shelf. Hans Windisch in his book Die Neu Foto Schule / The New Photo School (1938) uses Sodium Metabisulphite

The references Michael alludes to where there were issues in Germany pre WWII where with similar fixers using Potassium Metabisulphite with th the use of Potassium Metabisulphite stop baths taking the Potassium levels even higher and forming significant levels of Potassium Thiosulphate.

In comparison a typical Kodak hardening fixer contains less than 3.3% Potassium ions compared to Sodium which is very significantly less than the Agfa fixers. So with today's fixers we won't have issues with Potassium levels from carry over, particularly those that are unhardened. This is also why Kodak process machines can leave out the stop bath/water rinse step and just rely on passing paper between two rollers to reduce developer carry over into the fixer (which is replenished).

Ian

 

[Gerald C Koch]

What about Li salts? They are soluble and deliquescent. Maybe there is a balance between less lattice attraction with greater size and greater energy released with hydration of the smaller sized ions, so it isn't always clear.
I think potassium nitrate vs sodium nitrate is another counter example.

There are two inter related concepts both concerning electrostatics. For the sake of simplicity we will ignore other effects such as heat of hydration. For a molecule like sodium or potassium chloride to dissolve in water we must consider the energy difference between the two entities K0 and K+. In other words how much of the positive nuclear charge does a valence electron see? This is directly related to the amount of energy needed to remove it. The further the electron is from the nucleus the less charge that is seen (less energy needed). Then too any intervening electron shells also lessen the perceived nuclear charge. The electrons in these lower shells partially shield the nuclear charge. Obviously this situation favors larger ions as say potassium over sodium or lithium as far as solubility.

As a general rule potassium salts are more soluble than sodium salts. But as with any 'rule' there are exceptions.

 

[Photo Engineer]

I believe that if you use Potassium salts, you should check for complete silver removal and keep tabs on fixer exhaustion. That is all I recommend.

PE

 

[Ian Grant]

Very strange that Kodak themselves don't warn that liquid Dektol (Polymax) a liquid PQ developer using Potassium Carbonate might cause issues that don't occur with the MQ powder version of Dektol (using Sodium Carbonate). The reason of course that Kodak don't warn you is because there's never been an issue at all, a fixer would have collapsed long before any Potassium carry over would cause an issue because of the developing agent carry over.

All Ilford PQ print developers sold since the late 1950s have used Potassium Carbonate & Hydroxide with the exception of two powder developers which used Sodium Carbonate - Bromophen and ID-78 which was discontinued late 1960's or early 70's and is now replace by Ilford Warmtone developer a liquid version (using Potassium Carbonate), I should add the Ilford powder MQ developers were phased out in the 1960's all replaced by PQ versions.

You need to "check for complete silver removal and keep tabs on fixer exhaustion. That is all I recommend" I totally agree but that's regardless of whether a developer uses Potassium or Sodium or salts.

Ian

 

[Photo Engineer]

I refer you to the literature that says that with Potassium salts, the exhaustion can be worse.

Of course they do not warn you. No one does that wants to sell a liquid concentrate!

PE

 

[pdeeh]

Was it Zorkikat ? He was/is Philipines based. He successfully made Par-Rodinal due to supply issues in Philipines.

Sounds right.
His posts are still easily found.

But I also recommend APUG member dorff - his parodinal threads and posts are worth seeking out. He even attached a "parodinal calculator" (in the form of an excel s/s) to help one work out the right proportions of different ingredients to help one get all the sulfite into solution that's needed.

FWIW, I've made a few batches from that, using combinations of Sodium sulfite and metabisulfite, Potassium hydroxide and shop-bought paracetamol capsules.
It always worked just as well as commercial Rodinal, and kept perfectly well too (although I can't vouch for the decades that a commercial Rodinal will often keep )

 

[Ian Grant]

It wasn't Zorkikat it was KennyE who's posts here and the Digitaltruth Forum were works of pure fiction.

He came up with a formula that he claimed was 777 that had five developing agents in it

I refer you to the literature that says that with Potassium salts, the exhaustion can be worse.

Of course they do not warn you. No one does that wants to sell a liquid concentrate!

PE

No-one doubts that Potassium ions will potentially cause the formation of Potassium Thiosulphate in a fixer which is inactive (as a fixing agent), however that level has to be significant to cause even a slight issue and use of a stop bath (or water rinse with films) is sufficient to keep that level very low, very much lower than in a hardening fixer.

The reports of issues are in pre WWII Germany when the Potassium ions are over 22% compared to the level of Sodium in the Fixer formula itself and a Potassium Metabisulphite stop bath was used, and state that with a normal stop bath and fixers using Sodium (& Ammonium) salts (I'd add except when a hardener is used) there;s no problem.

With a stop bath or water rinse there really isn't a possibility of transferring enough Potassium ions to cause even a very slight issue, the transfer of Carbonate and developing agents will have a greater effect on fixer exhaustion.

What's more relevant is the archival testing by Ilford has ironically been done with PQ developers containing Potassium Carbonate and that's a benchmark that really put this into perspective, irrelevant as long as you're not using old fixer formulae using Potassium Metabisulphite

Ian

 

[pdeeh]

It wasn't Zorkikat it was KennyE who's posts here and the Dogitaltruth Forum were works of pure fiction.

Zorkikat posted plenty on Parodinal here, though he may well not have been the one to suggest boiling it

As for Kenny ... well, the less said the better really. Last sighted (by me at least) on Flickr, ranting conspiracy theories.

 

[Ian Grant]

As for Kenny ... well, the less said the better really. Last sighted (by me at least) on Flickr, ranting conspiracy theories.

I'm fairly sure I know KennyE's true identity, he has another older profile here but has only posted few times in the last 4 years, He seems to have really gone off the rails since his marriage break up in early 2013, his ex wife's dog wrote his Wikipedia entry. Well that's the name used by the author), He's tried to hide that but Wikipedia keeps a listing of all the edits and in one he states something that really exposes himself as a fraud

KennyE's posts were malicious and fraudulent however they also showed a surprising depth of knowledge of more obscure developers which was rather a big red flag, The way he writes (in terms of using English language structure) matched the other APUG member perfectly.n There were a lot of personal digs towards me as well in KennyE's posts.

Ian

 

[Gerald C Koch]

There is also my reworking of the Kalogen recipe which was sold commercially during WWI when Rodinal was not available in the US. It is very similar to the Agfa product but used metol and hydroquinone. Weigh out the metol and sulfite. Add a pich to the water and dissolve the metol Then add the remaining sulfite. The rest of the ingredients are added in order. A large amount of precipitate will appear when the hydroquinone is added but will dissolve when the hydroxide is added.

Distilled water (50°C) ……………………………………………… 750 ml
Metol …………………………………………………………………………………………… 12.5 g
Sodium sulfite (anhy) ………………………………………………… 150 g
Potassium bromide …………………………………………………………… 7.5 g
Benzotriazole, 1% …………………………………………………………… 50.0 ml
Hydroquinone ………………………………………………………………………… 45.0 g
Sodium hydroxide‡ …………………………………………………………… 22.5 g
Distilled water to make …………………………………………… 1.0 l

For use dilute 1+49. Typical development times are approximately 8 min @ 22C.

A sample now over 10 years old and still looking good.

 

[Photo Engineer]

Just do not ignore a possibility. That is all I am cautioning you all about as the Rodinal family is generally made up of all Potassium ion salts. The local concentration of potassium can be rather high at the bottom of a film structure if washing is not carried out properly before fixation.

PE

 

[hol571]

thanks for all the info

 

[chiller]

I'm interested to see posts again on this developer. Due to illness I haven't been in my darkroom for "a long period of time". Yesterday was tidy up in case I can remember how to use my cameras. In the process I found a half full 200ml bottle of Parodinal I made in 2012. Long story, short, I shot 2 sheets and processed one in Rodinal and the other in Parodinal. Almost identical densitometer readings. It has become an unintentional shelf life test.

My original formula was the Panadol tablets
Sodium Sulphite
and Potassium Hydroxide

I believe I used the methodology outlined by Dorff in his posts

This developer has seen seen 5 years of Australian summers with temperatures in my dark [shed] up to 48c.

 

[alanrockwood]

I'm interested to see posts again on this developer. Due to illness I haven't been in my darkroom for "a long period of time". Yesterday was tidy up in case I can remember how to use my cameras. In the process I found a half full 200ml bottle of Parodinal I made in 2012. Long story, short, I shot 2 sheets and processed one in Rodinal and the other in Parodinal. Almost identical densitometer readings. It has become an unintentional shelf life test.

My original formula was the Panadol tablets
Sodium Sulphite
and Potassium Hydroxide

I believe I used the methodology outlined by Dorff in his posts

This developer has seen seen 5 years of Australian summers with temperatures in my dark [shed] up to 48c.

Every interesting. Impressive shelf life under difficult conditions.

 

[Rudeofus]

Just do not ignore a possibility. That is all I am cautioning you all about as the Rodinal family is generally made up of all Potassium ion salts. The local concentration of potassium can be rather high at the bottom of a film structure if washing is not carried out properly before fixation.

There are some publications about potassium ion in fixer:
- The Journal of Photographic Science, 1966, vol 14, p 44ff, by K. Frank (Agfa Gevaert), titled "Some Aspects of Developer and Fixing Bath Concentrates Based on Potassium and Ammonium Salts Respectively". Frank makes strong claims about potassium in fixers ("proves useless as fixing agent", "is practically ineffective as fixing agent"), but does not back these up with experimental data or anything.
- US patent 5,358,832 claims, that fixers made from 0.5M Sodium Thiosulfate plus 0.5M Potassium Thiosulfate are profoundly faster than 1M Sodium Thiosulfate fixers, but slower than 1M Ammonium Thiosulfate fixers. Fixer capacity is not mentioned in this patent, only film clip clearing time in fresh fixer
- The Journal of Photographic Science, 1974, vol 22, p 274ff, by H. Hirsch (Kodak Harrow), titled "The Solubility of the SIlver Halides in Potassium Thiosulfate The Identification of the Solids in Equilibrium with Solution". Hirsch provides a thorough analysis of fixer capacities and compares solubility of AgCl, AgBr and AgI in Potassium Thiosulfate vs. Ammonium Thiosulfate. The article also details the reason for this difference in fixer capacity. There are poorly soluble mixed salts from Potassium, Silver, Halide and Thiosulfate, which inevitably show up as fixer becomes increasingly exhausted. Ammonium Thiosulfate fixer can dissolve two times as much AgCl, three times as much AgBr and four times as much AgI compared to Potassium Thiosulfate.

If I line up these three publications, my conclusions would be:

1. don't worry one bit about potassium ion carryover, it has no effect.
2. even 10% potassium in fixer will not have an effect on fixer capacity, that's why nobody has so far complained about Agfa 304
3. the issue is even less pronounced with photographic papers, which usually don't contain iodide.
   
4. 50% potassium in fixer will reduce fixer capacity somewhat with modern high iodide emulsions, but is still far away from "practically ineffective". Not everybody here uses fixer to exhaustion, so even 50% potassium ion may be a non-issue for many here.

 

[Kevin Caulfield]

It's nice to hear from you again, chiller. Thanks for the info on your Parodinal. I have a litre or so of home mixed Rodinal which I mixed up four years ago and I will test it again on a rainy day.

 

[chiller]

Thanks Kevin. I was rather surprised at the shelf life of the Parodinal and the negatives are very Rodinal like. Marginally different but very much alike.

 

[Harry Stevens]

Well here is what I have been using since 2014 in the UK. Not my formula from some fellows blog from South Africa who only had to hand the same chemicals as me. Works well for me.

Rodinal Type developer 250 ML

38g Sodium Metabisulfite +16g of Sodium Hydroxide

30 Crushed paracetamol tablets

20g Sodium Hydroxide

250 ml water

 

[removedacct1]

I found a half full 200ml bottle of Parodinal I made in 2012. Long story, short, I shot 2 sheets and processed one in Rodinal and the other in Parodinal. Almost identical densitometer readings. It has become an unintentional shelf life test..

Three years ago I was given a bottle of original Agfa Rodinal by a friend, and it dates from the mid-1980s. (It was an opened bottle and was opened at least 15 years ago) It works just fine and I am continuing to use it. How's that for shelf life??!