help choosing Rodinal

[ZorkiKat]

So, is this developer something that you make from over-the-counter ingredients? If so, how do you make it, or where can I read more about this process?

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

 

[pentaxuser]

I had bad experience using suringes with rodinal, despite my rinsing them, after some time, they become clogged, maybe I should have been more thorough with that rinsing

Try the 50ml Paterson or AP measuring cylinders. Very accurate to even 1 ml and none of the syringe problems you mention.

Rodinal has to be about the most economical developer ever. Good job the inventor made sure it lasted for years!

Pity about the grain issues with 35mm especially with 400 film which is my standard. At the next long sunny period in the U.K. say, 2015 I must get some Pan F and give it another go.

pentaxuser

 

[Gerald C Koch]

The developing agent in Rodinal is paraminophenol hydrochloride. Additional shipping regulations are based on the fact that Rodinal can be considered to contain potassium hydroxide, a very strong base. It is its presence that results in additional hazmat fees. Perhaps you might be able to obtain just the developing agent without incurring any hazmat fee. Both it and its parent base are very common starting materials for hundreds of other chemicals. There are many recipes on the net for various Rodinal like developers based on them.

Actually Rodinal doesn't contain any free potassium hydroxide but try explaining that to any government hack.

Any developer will exhibit edge effects if it is diluted enough. There is nothing mystical about Rodinal. There are many possible choices some of which may use more easily oblained ingredients. If you want edge effects you could try the Beutler formula or FX-2. Even D-72 diluted 1:9 or 1:19 can be used.

 

[Ian Grant]

The developing agent in Rodinal is paraminophenol hydrochloride.

No it isn't and NEVER has been.

Agfa used the free base p-Aminophenol in Rodinal which was known as Paramidophenol when Dr Momme Andresen first discovered it and formulated Rodinal.

He makes a point of differentiating it from the Hydrochloride which he used in Agfa 10.

Original Rodinal (still made by Calbe) doesn't contain any free KOH, but modern Agfa Rodinal after the early/mid 60's does,

Ian

 

[RobertV]

Well in case you need a high acutance developer you can try Beutler A+B. Very simple and cheap to make with only three ingredients:
Metol, Sodiumsulfite and Sodiumcarbonate (Soda). In fact Metol is the only photographic ingredient. Sodiumsulfite you can find at the swimming pool and Soda in the supermarket (Eur. 0,70 / kg).

Making the recept of Rodinal is not so easy. But having some 500ml bottles you can use it over a wide time schedule. It's the only liquid developer which has an extremely long lifetime.
I am using it for slow and medium speed classical cubical films only (25-200 iso).

 

[Gerald C Koch]

No it isn't and NEVER has been.

Agfa used the free base p-Aminophenol in Rodinal
Ian

I wouldn't say NEVER since the formula has changed many times.

When I first started using Rodinal over 40 years ago the concentrate was rather syrupy and lavender to purple in color. Then some years later Rodinal changed to a less viscous liquid which was brown in color. Obviously the formula changed. This what I think happened.

The free base was probably what was ultimately mixed to make the concentrate. However, the free base is very easily oxidized and rapidly becomes brown. When freshly prepared it is a buff color. When I would make one version of a Rodinal developer the directions called for using the hydrochloride salt and precipitating the free base with the addition of sodium carbonate. The final product was lavender in color just like the older form of the developer.

I suspect that later Agfa eliminated this step and started directly with the free base creating the brown product.

However, this does not explain the change in viscosity. The hydrochloride salt can be also used and this requires more potassium hydroxide to make the final product. This would result in a more viscous product because of the additional potassium chloride which is formed.

Of course we will never know because the exact formula has always been a sercret and has probably changed over the years. I suspect that the older lavender product was the result of the German mindset to make a pure product by using an extra step. Later economics took over and a less pure brown product was made.

 

[Ian Grant]

Rodinal NEVER used the Hydrochloride, that doesn't mean that the free base wasn't prepared from the hydrochloride first in the early days though. Over the years Agfa have published sufficient information to be certain of that fact.

Yes the way formulae was made changed over the years, mainly due to availability/form of raw chemicals changing. Initially the Potassium Sulphite was fromed by adding Potassium Hydroxide to Potassium Mtabisulphite. Later the Potassium Sulphite was supplied as a liquid concentrate.

Two major changes took place, the first in the 1930's when a benzene sulphonate compound was added, this acts as a wetting agent but has more important anti-oxidant properties.

The second major change was in 1964 after Agfa's merger with Gevaert when the amount of p-aminophenol was lowered by 20% and the pH increased. Previously Rodinal never had any free Hydroxide and a pH of 11.8, and crystals of the free base would often precipitate, as is still the case with Calbe's R09. The modern "Agfa" Rodinal has a pH of 14, and when fresh it should be almost clear just a faint straw colour as it's made and bottled under nitrogen.

Ian

 

[Gerald C Koch]

Thanks for the additional info. I knew that there was a change sometime in the sixties but couldn't remember the exact year. Memory fades too quickly sometimes.