Modern Rodinal Substitutes

[Ian Grant]

Ian Grant submitted a new resource:

(there was a url link here which no longer exists) - Modern Rodinal Substitutes

The formula for Rodinal R09 has never been officially published by Agfa. In the "Agfa" Book of Photographic Formulae, published by the Berlin Aniline Company in 1910, the company tells us:

As "AgfA"-Rodinal contains only traces of carbonic alkalies, the use of distilled water for dilution is not necessary. In connection with the use of "Agfa"-Rodinal the following remarks should be carefully noted:

In addition to neutral sulphite and water "Agfa"-Rodinal contains only an...

(there was a url link here which no longer exists)

 

[Uhner]

Many thanks.

This is indeed quite useful information. Especially if I ever use up all the bottles of Rodinal I have stored in the basement…

 

[Photo Engineer]

Some thoughts are appropriate here:

It was known that real Rodinal did not require a filtration step to prepare. This is one of my balking points with some of the formulas. It was made in-situ with no filtration. If you didn't know this fact, sorry to spring it now. In addition, there was a final ingredient added just as the material was packed into the bottles for shipping. Sorry again if you did not know that!

Going back to the formulas posted on the other thread, they seem to be quite alkaline, as much as 11.x and these current formulas seem to be more neutral. So, I ask, which is correct. This is more or less rhetorical as it won't help much except to know the "correct" pH, not what got us there.

And, use or even the exact amount of Metabisulfite used will tell us nothing about the final product as the M will rapidly decompose into Sulfite, Bisulfite and a mix of Sulfates in addition to any reaction with the p-Amino phenol.

PE

 

[Ian Grant]

Fair points.

First early Rodinal contained traces of carbonates from the precipitation of the free base, and it was known Agfa were starting with the Hydrochloride. We won't know exactly what stage, how or for how long they had to do this but at some point the free base was made and purified commercially.

Potassium Sulphite solution has a pH of 9-10 and Calbe RO9 has a concentrate pH of 11.8 which clearly indicates there's not much if any free Hydroxide which is Agfa's claim for Rodinal right from it's early days "Agfa"-Rodinal contains only an alkaline salt of Paramidophenol, but no excess of caustic alkali." So a substitute for R09 should only need enough Hydroxide to form the alkali p-Aminophenolate which will of course affect the pH.

Modern Agfa Rodinal uses an excess of hydroxide so has a pH of 14, a solution of 0.5% alone has a pH of 13 and there is more free Hydroxide than that in the formula which along with the sulphite & alkaline p-Aminophenolate will take the pH to around 14.

I'm not suggesting using Metabisulpite, that was an early method used but requires far more hydroxde to first neutralise it and then form the sulphite, Dr M. Andresen (Agfa) certainly used metabisulphite as the source of Sulphite in some of his formulae, and other contemporaries were doing the same. The major issue is the amount of hydroxide needed will vary depending on the condition and free SO2 content of the powder or solution. This just adds an other unnecessary variable.

It's quite probable that RO9 may need final adjustments prior to bottling at a commercial level. One reason Agfa in West Germany changed the formulae was to make it cheaper & easier to manufacture, by using excess Hydroxide the step needed to balance the p-Aminophenol against the hydroxide has been eliminated and also allows a lower concentration of p-Aminophenol to be used while actually increasing the developer's activity.

Ian

 

[Photo Engineer]

Again, good points Ian. I appreciate the discussion. I have been fascinated by Rodinal for years.

I might add that I was toying with the idea that Agfa used the HBr salt of the p-AP to get the Bromide in the final developer, as the Chloride might be a variable that they did not want. OTOH, the Chloride may have functioned as it does in Microdol X to an extent adding its solvent powers to the Sulfite. IDK. All fascinating.

The final step was indeed a pH adjust due to the fact that the "system" was in an unbalanced state for hours after mixing for some reason and had to be rebalanced. This was one of the sticking points of Rodianl manufacturing.

PE

 

[Ian Grant]

Rodinal has always used the free base in the developer itself, right from it's initial formulation, Dr Andresen's contemporaries were well aware of this. It certainly appears they didn't want the Chlorides present in the developer.

If I was making a developer like the old type Rodinal, Calbe R09 or similar, on a commercial scale I think I'd mature it with a very slight excess of Hydroxide, and then use a small addition of Potassium Metabisulphite to remove the excess hydroxide. You could back titrate a sample to determine the exact amount to add, once there's no excess hydroxide the free base begins to precipitate, but the pH will also probably drop at the same time. It's hard to know without trying it.

Judging from Patents on p-Aminophenol manufacture it appears there must also have been issues with controlling the purity during manufacture, so possibly other tests were conne before finalmadjustments & bottling.

Commercial alternative p-Aminophenol developers were available by the early 1900's Johnson's Azol was an early alternative to Rodinal, again using the free base. Ilford introduced it's version Certinal in 1909

Kodak's approach was to use p-Aminophenol Oxalate, they sold this as Kodelon and presumably it's the developing agent in "Kodilon" which was their highly concentrated liquid developer, and competitor to Rodinal. Kodak also sold p-Aminophenol hydrochloride as Kodelon. I have only ever seen references to "Kodilon" in UK Kodak Formulary as a commercially available liquid para-aminopheol type developer.

It appears when p-Aminophenol hyrochloride is used in combination with a second developing agent and excess carbonate there's less of an issue with the Hydrochloride, and it was used in other Agfa, Kodak, Ilford etc developers.

Lowe used "Gradol" which was the Edwal company name for p-Aminophenol Sulphate.



I deliberately didn't give the formula for J. Desalme's "Concentrated Paraminophenol Developer of the Rodinal Type" because there are some issues with the weights & conversions & concentrations used in the British translation of L.P.Clerc's book. The UK editor of the book George E. Brown, the Editor of The British Journal of Photography, and also the British Journal Photographic Almanac, died in 1934, and the book wasn't published until 1937 some considerable time after his death. (It is a large and comprehensive book). G.E. Brown was the Tangye Scholar for Chemistry 1892-3, at Birmingham University and would have had a full understanding of Photographic Chemistry.

However Brown also published the same formula in the British Journal Photographic Almanac.

Paramidophenol Developer

Solution A

Paramidophenol hydrochloride 68 g
Water, hot, 600 - 700 ml

Filter solution if necessary.

Solution B

Sodium Sulphite 9.36 g
Sodium Carbonate (anhyd) 31.2 g
Water to 200 ml


Add B. to A. The paramidophenol is thrown down.
When mixture is cool filter off the deposit on cloth, and let the paste dry until its bulk is not more than 300ml.

Then, in a graduate, mix with it 100 ml of soda bisulphite lye 35° B. and add strong solution of caustic soda of 40° B. (about 50%) until the base is just dissolved. Water is then added to make 500 ml. The solution is diluted 20 to 30 times for use.

Sodium Metabisulphite (soda bisulphite) and Sodium Hydroxide (caustic soda( were commonly sold as a solutions.

The Sodium Metabisulphite 35° B, is approx a 28-30% solution and it is still commercially available in this form.
The Sodium Hydroxide 40° B, is closer to 38% than the 50% given.

The yield of p-Aminophenol free base is approx 50.97 if conversion 7 recovery is 100%.

The Avoirdupois & Metric conversions/proportions are correct, this formula uses about 10% of the metabisulphite advocated in other similar formula which allows a higher concentration of the developer.

I've only added it to the thread to show how easily the free base can be formed.

Ian

 

[gainer]

I set out to try your formula. I found I had little more than 300 grams of Potassium sulphite left. It's s a good thing, because that amount would not dissolve in a liter of hot water. I added 27 grams KOH next, and then 41 grams of p-aminophenol base. I can't tell if the sediment is all sulphite, but the color is light orange to my 82 year old eyes. A snip test of 1+50 dilution seemed about normal. It looks about like a batch I made a while ago that has still not turned the deep brown, but nevertheless works very well.

Have you tried dissolving 384 grams of anhydrous Potassium Sulphite in a liter of water? I have heard that number before, but it doesn't appear in my CRC Handbook. My sulphite came from Photographers' Formulary.

I'll look at it again tomorrow and do a test roll.

 

[david b]

I have no idea what you guys are talking about, but find it awesome and fascinating.

 

[Ian Grant]

I set out to try your formula. I found I had little more than 300 grams of Potassium sulphite left. It's s a good thing, because that amount would not dissolve in a liter of hot water. I added 27 grams KOH next, and then 41 grams of p-aminophenol base. I can't tell if the sediment is all sulphite, but the color is light orange to my 82 year old eyes. A snip test of 1+50 dilution seemed about normal. It looks about like a batch I made a while ago that has still not turned the deep brown, but nevertheless works very well.

Have you tried dissolving 384 grams of anhydrous Potassium Sulphite in a liter of water? I have heard that number before, but it doesn't appear in my CRC Handbook. My sulphite came from Photographers' Formulary.

I'll look at it again tomorrow and do a test roll.

Patrick, photographic grade Potassium Sulphite is sold as a 45% w/w solution, so 384 will dissolve easily, but maybe not quickly

It's solubility in water is 655 g/l, substantially higher than 384, this is why Potassium salts are used in liquid concentrate developers

In fact the supplier I'm looking at doesn't sell photographic grade Potassium Sulphite as a solid instead 45% W/W containing approx 450g/l:

STANDARD PACKING:

* 250 Kgs. HDPE Drum
* 30 Kg. HDPE carboys
* 1000 Liters Intermediate Bulk container (IBC)
* 20 MT Bulk Liquid Bag (Flexi bag)

In Germany BASF supply this grade, in the US Mallinckrodt Baker, it's standard.

So to answer your question, yes I have made up concentrated stock solutions of Potassium Sulphite and Carbonate. I've started using the Potassium salts when making up concentrates of my print developers, replacing Sodium Sulphite & Sodium Carbonate in the formulae with the Potassium salts and KOH. This is done commercially to allow higher concentrates which won't precipitate during storage.

Ian

 

[gainer]

"Patrick, photographic grade Potassium Sulphite is sold as a 45% w/w solution, so 384 will dissolve easily, but maybe not quickly."
How about overnight, starting in 160 F water? I stirred it for a good half hour before going to bed. That doesn't explain what happened here. This morning, I decanted clear liquid and found that another liter of water was required to dissolve the remainder. That solution is quite a potent developer, but not as strong as what I decanted.

The CRC Handbook shows K2SO3.2H2O, with solubility in cold water of 1000 g/l. My 320 g/l certainly should have dissolved, even if I had the anhydrous, in the hot water.

 

[Photo Engineer]

That 1000 g/L must be a typo. Think about it Patrick. That does not leave much room for water at all!



PE

 

[Ian Grant]

It may not be. 1100gms of Potassium Hydroxide will dissolve in a litre of water, at 25°C that rises to 178g at 100°C.

So are the two figures written in different ways - If you start with 1 litre then that will dissolve 1000g but the final volume will be more than a litre, or conversely that a 1 litre saturated solution of Potassium Sulphite will contain 655g ?

Either way something sounds strange because 380-400 gms of Potassium Sulphite should dissolve fairly easily in water.

Potassium Sulphite is a slightly better antioxidant than Sodium Sulphite and is used as a anpreservative and anti-browning agent in the food instry.

Ian

 

[Shawn Dougherty]

I have no idea what you guys are talking about, but find it awesome and fascinating.

My thoughts as well. I've got this all saved on my hard drive in case, God forbid, I'm unable to buy Rodinal commercially at some point in the future. Thanks fellows. s

 

[Photo Engineer]

It may not be. 1100gms of Potassium Hydroxide will dissolve in a litre of water, at 25°C that rises to 178g at 100°C.

So are the two figures written in different ways - If you start with 1 litre then that will dissolve 1000g but the final volume will be more than a litre, or conversely that a 1 litre saturated solution of Potassium Sulphite will contain 655g ?

Either way something sounds strange because 380-400 gms of Potassium Sulphite should dissolve fairly easily in water.

Potassium Sulphite is a slightly better antioxidant than Sodium Sulphite and is used as a anpreservative and anti-browning agent in the food instry.

Ian

Ian;

What does your first sentence mean? I'm totally confused. 1000g rises? to 178???

As for the second, my handbook says that K2SO3.2H2O is soluable in 3.5 parts of water. This differs from all of the figures given so far. That is about 28%, but adjusting for the water of hydration will increase that value. I would have to figure out the contribution, but it does sound as if a 40% solution is reasonable.

PE

 

[David A. Goldfarb]

And is the motley paRodinal formula so far beneath contempt as not to merit even a mention in this thread?

 

[Ian Grant]

Typo/slip Ron, sorry the figures were g/100ml so I missed the zero from 1780 scaling up to a litre

Here's BASF's Potassium Sulphite 45% solution, the 650g/litre seems a bit odd because other manufacturers Mallinckrodt etc say 450g/litre for the 45% solution.

The main source I looked at only sells photographic chemicals and 45% solution is the only Potassium Sulphite they sell.

Ian

 

[Ian Grant]

And is the motley paRodinal formula so far beneath contempt as not to merit even a mention in this thread?

Best kept for headaches

Back in the late 70's while working as a photo-chemist it was suggested that I might make & sell Photochemistry. At that point we had a very practical Monobath which we'd devised for a specialist application but it also worked extremely well with both films & papers.

These days it's a bit late to think about entering the market, the number of manufacturers greatly out-strips the number of film/paper manufacturers by a huge margin

But there's still a niche for specialist chemistry, and perhaps there's a few things up my sleeve, however they would go out through existing suppliers. I've no wish to be a Capitalist

Ian

 

[Photo Engineer]

Ian;

That is probably a good point. A lot of slips in formulas it seems. Even we are not immune. I just goofed badly in another thread identifying an organic structure!

As for the BASF figure, I would have to do the math carefully but the ratio of 650/450 might be thought of as the ratio of the Dihydrate to Anhydrous. IDK. But, OTOMH it does not look right as the difference is only 36 grams per mole or a difference of about 1.2xxx. The ratio of 650/450 is more like 1.444.

PE

 

[David A. Goldfarb]

Best kept for headaches

Ian

It's actually surprisingly good--kind of like Rodinal with a little of the edge burnished off or Rodinal+sulfite. Of all the kitchen chemistry formulas out there, it's the only one I would really use for anything other than the novelty of developing film in household chemicals.

 

[Mahler_one]

Same here David...great stuff.

Ed

 

[Ian Grant]

The Rodinal + Sulphite goes back to the pre 1964 Agfa Rodinal, and makes sense because the Calbe R09 & pre-War Rodinal formula contained less sulphite.

Many people comment on how watery Calbe R09 is in comparison to the Agfa/A&O etc product, and it's the high sulphite level that makes the difference.

Ian

 

[gainer]

That 1000 g/L must be a typo. Think about it Patrick. That does not leave much room for water at all!



PE

The CRC table actually says that 100 grams will dissolve in 100 cc of cold water. It doesn't say what the final volume will be. That would form a 50% solution by weight, which K2CO3 can do. It also says that <100 grams will dissolve in hot water, but not how much less. However, I was not approaching the stated solubility in cold water, and heating usually speeds up solution, so I 'm mystified about why the 320 grams wasn't dissolved after a half hour of stirring and even after sitting overnight.

 

[Photo Engineer]

Well, based on that Patrick it is not 1000 g/l of solution, it is 1000 g / liter of water which will be more than 1 liter and close to 2 Kg in weight. As you say a 50% wt/vol solution. Be careful, this will become very very hot during mixing and may boil over.

PE

 

[gainer]

Well, based on that Patrick it is not 1000 g/l of solution, it is 1000 g / liter of water which will be more than 1 liter and close to 2 Kg in weight. As you say a 50% wt/vol solution. Be careful, this will become very very hot during mixing and may boil over.

PE

I knew that.
Right there is another clue that something was wrong with my Potassium sulphite. I started with hot water and adding the sulphite cooled it considerably. But I was adding 320 grams to 750 ml.

 

[gainer]

Well, based on that Patrick it is not 1000 g/l of solution, it is 1000 g / liter of water which will be more than 1 liter and close to 2 Kg in weight. As you say a 50% wt/vol solution. Be careful, this will become very very hot during mixing and may boil over.

PE

Also, I believe I said "50% by weight" , which is exactly true. 50% of the weight of that solution would be K2SO3.2H2O. It would take some calculation to find what fraction of the weight of the solution is K2SO3.