Rodinal: "old" vs "new" formula

gainer said:

That's not evidence of another agent. I can get fog with p-aminophenol. As a rule, a developing agent will be a potentially harmful ingredient that should be reported in the MSDS. Is there any other evidence for the presence of more than one agent? In any case, a developer containing p-aminophenol as the sole developing agent can produce the same characteristics as the current AGFA product, so one might wonder why AGFA would bother to complicate matters.

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I agree that the presence of the restrainer isn't conclusive proof of another developing agent. I imagine you probably could induce fog with Rodinal by increasing it's activity. In fact, I'd be interested to hear if the pH of Agfa Rodinal and traditional Rodinal differ substantially.

The reason for the use of a second developing agent, is probably cost-related. p-Aminophenol HCL is considerably more expensive than Hydroquinone and even a bit more expensive than Metol. Exploiting superadditivity with a second developing agent might improve the economics of manufacture.

That being said, 1L of the traditional formula requires about 600 g of three different solutes. Potassium metabisulfite isn't particulary cheap, either, and traditional Rodinal requires 300g in a liter of stock solution.

As you said, why would AGFA bother? All I can come up with is cost to answer that question.

Well, I found that neither the hydrochloride of p-aminophenol nor the metabisulfite are necessary. The end products are the same as if you had used the p-aminophenol base and plain sulfite except for some chloride of potassium or sodium, depending on which sulfite and/or hydroxide you used.

The cost of a product is usually much more than the cost of the raw materials. If the cost of the process of arriving at the same end result can be reduced, even if the raw materials cost more, it may be that the end cost may be less.

IIRC, the last time I bought any, p-aminophenol base and the hydrochloride were about the same price per pound, and more of the hydrochloride is required because its molecular weight is higher and the same number of molecules is required in either case. I contend that dumping measured weights of p-aminophenol, sodium or potassium sulfite and sodium or potassium hydroxide into a vat with a measured amount of water and stirring will be cheaper in the long run than a method that requires careful titration.

It doesn't make a lot of difference to me which is the way AGFA does it as long as the way I do it works the same.

Speaking of Metol, it is possible to use Metol in place of p-aminophenol with some advantages.

Dave,
The formula I use is not the one you will get from PF. Mine has only p-aminophenol base, sodium or potassium sulfite and sodium or potassium hydroxide in measured amounts, putting the p-aminophenol and sulfite in water then adding the hydroxide. If you feel the need of the chloride ion, you can always add some canning salt or non-iodized table salt.

Gainer's EZ rodinal:
(there was a url link here which no longer exists)

Hello:

The Pictorial Cyclopedia of Photography gives a formula for a p-aminophenol concentrated developer ("Rodinol")as

para-aminophenol (free base) 100g
Potassium metabisulfite 300g
500cc Water
Titrated with minimal amount of concentrated potassium hydroxide and made up to
1 liter.

yours
Frank

fpjohn said:

Hello:

The Pictorial Cyclopedia of Photography gives a formula for a p-aminophenol concentrated developer ("Rodinol")as

para-aminophenol (free base) 100g
Potassium metabisulfite 300g
500cc Water
Titrated with minimal amount of concentrated potassium hydroxide and made up to
1 liter.

yours
Frank

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Yes, and when all the reactions due to mixing have completed, the resulting solution is equivalent to one containing potassium aminophenolate, potassium sulfite and water. This one does not even have the potassium chloride that would result from the use of p-aminophenol.HCl. whether you use the sulfite or the metabisulfite, the result is potassium sulfite and water. Titration usually involves adding one solution to another until a desired pH is reached. I have not seen any statement of the target value of pH. The leaving of a few undissolved crystals may serve the purpose of a pH indicator.

Not anything special, just tests without densitometer. I had a long expirience with Foma R09 (as wtitten by Anscojohn, originally from ORWO company, and I think it is very old formulae), because original AGFA rodinal was not available due to their financial problems. However now (don't know if it true, that AGFA photo division was bought by MACO) original rodinal is available. It is new formula. I tried to find what is difference in mixture form literature, brochures and internet and didn't succeed. But my personal expirience for Rodinal and R09 is, that results are very very similar, if not the same. But also many people develops in their own estimated times. The greatest difference is in color ... R09 is very dark brown-red, while Agfa rodinal is much more translucent and when diluted pink. It is advantage when used (in small amounts) for positive development. I heard from some people they add sometimes small amount of rodinal to their standard positive developer ...

Sorry for so many words.
r.

A&O does indeed produce the whole line of Agfa b/w chemicals. Here is their webpage related to this endeavor.

Dead Link Removed

PHOTOTONE said:

A&O does indeed produce the whole line of Agfa b/w chemicals. Here is their webpage related to this endeavor.

Dead Link Removed

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Hmmm... I have seen that fact posted on the forums repeatedly, but this is the first time it sunk in that they are actually using the Agfa name as well. Anyway, I just got some of that from Freestyle, but haven't had the chance to try it yet. Never enough time.

-Dave

Yes, I have a couple bottles of AGFA Rodinol that I bought from Freestyle in 9/06.

I've tested it and it works just like my 1978 bottle of AGFA Rodinal (also from Freestyle).

And so does the Gainer p-aminophenol (base) recipe that I mixed from scratch, using p-aminophenol (base) from Photographer's Formulary.

Dave Krueger said:

Hmmm... I have seen that fact posted on the forums repeatedly, but this is the first time it sunk in that they are actually using the Agfa name as well. Anyway, I just got some of that from Freestyle, but haven't had the chance to try it yet. Never enough time.

-Dave

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Yes, they acquired the rights to the chemicals and the Agfa brand for chemicals. Also, I am sure you are aware that whenever you go to purchase Kodak D-76, HC-110, or whatever Kodak chemistry you use, that Kodak did not make it! They sold their chemical manufacturing plant months ago, and now contract-out for the chemistry. It should be of identical quality though, as the same people make it (former employees).