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 alkaline salt of Paramidophenol, but no excess of caustic alkali.
PDF Rodinal 1910
However it's possible to make formulae that's close to the current versions.
Original Rodinal contained p-Aminophenol (once called Paramidophenol by Agfa) and this was formed by precipitation of the free base from p-Aminophenol hydrochloride using sulphite and carbonate (hence Agfa's comment "contains only traces of carbonic alkalies".
The formula for Rodinal has changed and evolved presumably as high grade p-Aminophenol free base became commercially available, allowing Rodinal to be completely free of carbonates.
J. Desalme published a " Concentrated Paraminophenol Developer of the Rodinal Type" in 1913, this was later included in L.P. Clerc's book "Photographic Theory and Practice".
Sodium Carbonate & Sodium Sulphite are added to a solution of p-Aminophenol Hydrochloride which precipitates the free base, which is filtered and collected.
The paste of p-Aminophenol free base is then added to a solution of Sodium Metabisulphite and Sodium Hydroxide added until all the free base is dissolved, finally a small amount of Metabisulphite is added until the first crystals of p-Aminophenol free base begin to form again.
This mirrors Agfa's own description of early Rodinal, and accounts for the traces of carbonates, and the "no excess of caustic alkali". (J. Desalme was a photographic chemist specialising in aminophenols and other developing agents particularly for colour processing).
Now we reach a point of contention "Free base" or "Hydrochloride", genuine Rodinal has always been made using the Free base of p-Aminophenol . (50g of p-Aminophenol is equivalent to 66.2 g p-Aminol hydrochloride). There is no evidence to suggest that Rodinal of any form has ever contained p-Aminophenol Hydrochloride.
The MSDS sheets for both Rodinal and Calbe R09 show clearly that both developers contain p-Aminophenol free base (CAS 123-30-8) and not p-Aminophenol hydrochloride (CAS 51-78-5).
Making a Rodinal substitute with p-Aminophenol Hydrochoride will leave free chlorides in the solution, and neutralise more Hydroxide, the amount of developing agent would need to be increased along by a factor of 1.33 and also more KOH added.
Data on early Rodinal is hard to find but in a thread on Photo.Net "Edward Zimmermann" wrote:
The formulas for Rodinal, resp. R09 (1964 to present), have never been published. The patent is for Paramidophenol developers and there are many recipes making the rounds since the late 1800s. One of the most famous is attributed to Eder. From my copy of Spörl and Neumann, "Fotografisches Rezeptbuch" 1943 edition, p.50):
- Paramidophenol 50g
- Kaliummetabisulfit [Potasium Metabisulfite] 150g
- Wasser 625ccm (ml)
Then a solution of
- Ätznatron [Sodium Hydroxide] 215g
- Water 500ccm (ml)
is slowly added untill the cloudyness breaks. According to the book it says this is typically around 350ml.
Then the solution is diluted with water to make 1 liter.
My note: 350ml of the Sodium Hydroxide solution contains 150.5 gms Sodium Hydroxide.
The same formula was published in the British Journal Photographic Almanac (1910 & earlier) as:
Potassium metabisulphite 300g
Distilled water 1 litre
Dissolve in the above order and add gradually:
Caustic soda or potash to dissolve the precipitate first formed.
For use, dilute 1 part. with 10-20 parts of water.
No final volume of solution is given but it's likely to be 2 litres if you want the equivalent of early Rodinal.
It's important to note that these sources clearly indicate the use of the free base, as they go on to also include p-Aminophenol Hydrochloride film developers. These are in the 1910 "Agfa" Book of Photographic Formulas, the 1910 BJP Almanac and Ed Zimmermann's book all from quite different sources & countries.
However other versions of this formula appear in various books from the early 1900's onwards, but using p-Aminophenol Hydrochloride, because of the difference in Molecular Weight and the effects of the additional Hydrochloride they won't be quite the same. Dr M. Andresen, of Agfa, who discovered & patented p-Amaninopheol and designed Rodinal published it himself in the "AGFA Photo-Handbook" he did not claim it was similar to Rodinal, listing it as - Formula 21: Concentrated single solution. (As above proportions but using p-Aminophenol Hydrochloride).
L.P.Clerc and others indicate that Potassium Metabisulphite was the preferred source for the Sulphite in Rodinal, Potassium salts are used in preference to Sodium because of their greater solubility in water which becomes far more important in concentrated developer solutions. Metabisulphite and Hydroxide form Sulphite in solution.
At some point before or during WWII Agfa began using Potassium Sulphite and also adding Potassium Bromide and an anti-foggant to Rodinal. It's entirely possible that Agfa modified Rodinal so that it was more suitable for roll & particularly 35mm films which became cfommon in the 1930's.
Some have made the assumption that this formula might be "Classic Rodinal" but if we compare it to a modern MSDS's it's only close s to Calbe's R09 MSDS for the p-Aminophnol.
P-Aminophenol 50g - 5%
Potassium Metabisulphite 150g - 15%
Sodium Hydroxide - very approx 150g - 15%
Water to 1 litre
Calbe R09 MSDS
Potassium Sulphite 30%
Potassium Hydroxide 4%
However Potassium Metabisulphite is quite acidic in solution and will neutralize a considerable proportion of the Hydroxide. Replacing it with Potassium Sulphite cut's the amount of Hydroxide needed very substantially. Potassium Metabisulphite 5% solution has a pH of 3.8 - 4.6, while a similar Potassium Sulphite solution has a pH of 9 - 10
Only one parameter seems to stay constant from early published alternatives through to Orwo/Calbe R09 - the fact that Rodinal is a 5% solution of p-Aminophenol free base in a sulphite solution, with no excess of alkali. It's reported that the Calbe product usually has a few crystals of the free base in the bottom of the bottle, which indicates no excess of Hydroxide.
The British RAF report into the "Agfa Film Factory - Wolfen" reported by G.C. Brock, London : H.M.S.O. gives a formula for Rodinal as:
Dissolve 34 kg of para-aminophenol in 340 litres of water. Add 558 kg of a 30% solution of potassium sulphite at 55C followed by 50 kg of a 34% potassium hydroxide solution, then 5.52 kg of potassium bromide in a little water. Add 42 g P.1347 (an Agfa-specific anti-foggant). Filter and allow to stand for 14 days.
Knowing the Specific Gravities etc this seems to be around:
Potassium Sulphite 128.08kg
Potassium Hydroxide 12.57 kg
Potassium Bromide 3.75 kg
We aren't given a final volume, but if we relate this to the 5% p-Aminophenol of the Calbe MSDS this works out as:
Potassium Sulphite 19%
Potassium Hydroxide 1.85%
Potassium Bromide 0.77%
But the Calbe/Orwo version of R09 is the pre-WWII formula and it's MSDS is
Potassium Sulphite 30%
Potassium Hydroxide 4%
Potassium Bromide - not included (below 1%)
Unfortunately we can't really completely trust the RAF report, none of the Allied F.I.A.T. reports about Agfa products is entirely accurate, after all some Agfa employees were former members of the National Socialist Party (Nazi's). There is insufficient Potassium Hydroxide to react with the p-Aminophenol free base, and it is possible the resulting solution was then adjusted until the free base had just fully dissolved.
Patrick "Gadget" Gainer has published "EZ Rodinal" which in terms of its ratio of p-Aminophenol to Potassium Hydroxide is probably close to Calbe R09 as there will be no excess of Hydroxide, the weights in brackets have been scaled to give a concentration of 5% p-Aminophenol.
To 400 ml water, add:
Sodium sulfite (anhyd) 85 g (106.3)
p-Aminophenol base 40 g (50 g)
Stir well. Add
Sodium hydroxide 13.8 g or Potassium hydroxide 19.2 g (24g)
Add water to make 500 ml. (1 litre)
If EZ Rodinal; is adjusted a little further by adding 300 g of Potassium Sulphite in place of the Sodium Sulphite, some Potassium Bromide added plus some Benzotriazole and Potassium Hydroxide added slowly until the free base just dissolves
EZ Rodinal New (Calbe R09 substitute)
To 800 ml water, add:
p-Aminophenol base 50 g
Potassium sulphite (anhyd) 300 g
Potassium hydroxide 24 g
Potassium Bromide 0.8 g
Benzotriazole 1% 10 ml
Water to make 1 litre)
This would be a lot close to the pre War formula and Calbe RO9, although this is itself now being made in a more concentrated form so that the dilutions & dev times are more comparable to Agfa /A&O Rodinal (post 1964)
Patrick's second Rodinal substitute formulae is close to the Bayer/Agfa/A&O MSDS data-sheets for modern Rodinal:
p-Aminophenol 4.1% (A&O)
Potassium Sulphite 30-40%
Potassium Hydroxide 2.7% (A&0)
Potassium Bromide 1-5%
Anti-foggant - not specified
Gainer Rodinal Substitute
To about 750 ml of water at room temperature, add
p-Aminophenol 38 g
Sodium sulfite (anh) 160 grams
Sodium hydroxide 23 grams
Water to 1 liter.
This is on the right track, you need to use the free base and an excess of Hydroxide unlike the older R09 formula which has nearly 20% more p-Aminophenol and also requires using at a higher concentration to get equivalent results.
In a post about Patrick's version a comment was made about the pH at 1:50 being roughly 11.6, Agfa Rodinal has a stock concentrate pH of 14 and a dilute pH of 11.55 so if this is the case Patrick's formula is about right, except too little Sulphite and there's no Bromide or anti-foggant.
Agfa's modern Rodinal 1964 onwards uses an excess of Hydroxide and as a consequence is more active despite the lower level of p-Aminophenol than the previous formulae. Calbe R09 concentrate has a pH of 11.8.
This is what I would use as a starting point for a good modern substitute:
p-Aminophenol.(free base) ................... 41 g
Potassium sulphite (anh) ..................... 348 g
Potassium Hydroxide ........................... 27 g
Potassium Bromide ............................. 10 g
Benzotriazole 1% ............................... 10 ml
EDTA Na4 (optional) ........................... 6 g
Water to make .................................. 1 litre.
If necessary adjust to pH 14
The balance of the Bromide & Benzotriazole may need adjusting upwards..
The mixed developer should be left a couple of weeks before use.
Contrary to what has been written in some books Rodinal has always used the free base of p-Aminophenol although in the early days this was prepared from the Hydrochloride first.
Ian - going back a bit - you seem to be hung up on this quote above.
Originally Posted by Ian Grant
I read that as when Agfa used hydroxide in the preparation, they were able to use high quality hydroxide. Poorer quality hydroxides would certainly contain carbonate. And hydroxide that sits around with exposure to air will sequester carbonate. So it could be both a manufacturing and storage issue when compared to earlier sources of hydroxide.
So I take their statement as one that means they were able to manufacture the hydroxide with very little carbonate content - not that carbonate was used at any point in the process or from any other ingredients. I don't think that statement has anything to do with preparation from free base.
Perhaps they were using sealed reaction vessels and perhaps they had nitrogen atmospheres to protect the hydroxide solution from atmospheric carbon dioxide. It would denote a couple steps up in manufacturing technology from years previous.
For up from the ashes, up from the ashes, grow the roses of success!
Bill - are you saying you are suprised that a 3% solution of potassium hydroxide has a pH of 14? If so, here's the way to calculate it.
Originally Posted by billtroop
A 3% solution is about 0.53M KOH.
Calculate pOH first:
pOH = -log10[OH-]
pOH = -log10[0.53M]
pOH = 0.276
Then calculate pH:
pH = 14 - pOH
pH = 14 - 0.276
pH = 13.72
A 0.53M KOH solution should have a pH of about 13.7. That's close enough to pH 14 for my book.
If that's not what you are saying, then don't worry, it's my mistake...
For up from the ashes, up from the ashes, grow the roses of success!
We have to remember that Agfa's parent company was already a highly sophisticated chemical manufacturer by 1897 so it's likely that they had a high degree of control over the purity of chemicals like hydroxides used in developers.
Originally Posted by Kirk Keyes
Reading work by contemporaries of Andresen working with similar developing agents they were aware of the differences between the free base & different salts of compounds like p-Aminophenol.
Mees & Sheppard did work with p-Aminophenol back in their days at Wratten & Wainwright, how much I don't know without trying to find copies of the book and papers they wrote (while at Wratten). This work is held somewhere along with the work of J.Desaume in Kodak archives.
Kodak also researched p-Aminophenol, Sheppard's name crops up again and their choice of salt was p-Aminophenol Oxalate (Kodelon) which presumably what they used in Kodinol.
George Brown, the Editor of the BJP from 1904 until 1934 would also have been well aware of the differences between the free base & the hydrochloride, (he was himself a Chemistry Scholar) he would have known Mees & Sheppard, he lists their Wratten Formulae in the 1910 BJP Almanac and makes a point of listing a concentrated p-Aminophenol developer, alongside a p-Aminophenol Hydrochloride developer.
What's perhaps more important is we know that by the 40's and through to today Agfa/A&O and Calbe have definitely used the free base, so any attempt at making our own needs to do the same.
Shows how much chemistry (& Biochemistry) I've forgotten, I'd just use a pH meter these days
Originally Posted by Kirk Keyes
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As a historical side note: there was no `parent company´. Rather Agfa was a chemical company mainly producing dyes, that gave a try on producing a photochemical product (a film developer by Andresen) in 1889. That date given by Ian, 1897, was the introduction as brand name of their abbreviated company name.
Even when Agfa started to build their film manufacturing plant in Wolfen the sales of their photochemical products was about 9%. Even in 1923 it was only 36%. The photochemical branch (department from 1891 on) was not independant.
Agfa as a whole ended their independance when they opted to become a part of IG Farben.
Last edited by AgX; 08-29-2009 at 04:09 AM. Click to view previous post history.
Good point, but it would have been a division, and it's the Agfa brand name that we all know. In the US the company was the Berlin Aniline Works.
AGFA was the brand name for all products by "Actien-Gesellschaft für Anillin-Fabrikation". Though the consumer only new it at through their photographic products.
Would you be able to design an environmentally friendly Rodinal substitute? Paramidophenol is a verifiable water pollutant and injurious to health.
p-Aminophenol is far more widely used in hair dyes and in far larger quantities than the volumes of Rodinal used.
The actual amount of p-Aminophenol, sulphite and hydroxide used per film is likely to be far less polluting than most more concentrated developers (at working strength), somewhere I have the Toxicology figures for Colour processing because I had to deal with the regulatory authorities, in the UK there it is the water boards, because they have to treat the water and make it fit for human consumption.
In an average household there are far worse pollutants disposed of in a normal week.
Even a developer like Xtol used 1+1 is far worse than dilute Rodinal, so coming up with something more environmentally friendly is going to be difficult.
fyi- I've had to edit some bickering out of this thread and get it back on topic.