Just for Ron (PE)
I think Patrick "Gadget" Gainer has come closest to publishing a rough Rodinal (Agfa/A&O) substitute with this:
To about 750 ml of water at room temperature, add
p-aminophenol...............38 grams
sodium sulfite (anh)........160 grams
sodium hydroxide............23 grams
Add water to make 1 liter.
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. (The concentrate has recently been changed).
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.
This is what I would use as a starting point:
Rodinal Sustitute
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
Some notes;
Agfa Rodinal has always contained the p-Aminophenol free base although the Hydrochloride was used initially in the preparation of the free base.
The balance of the Bromide & Benzotriazole may need adjusting.
Agfa's modern Rodinal 1964 onwards uses an excess of Hydroxide and as a consequence is more active despite a lower level of p-Aminophenol than the previous formulae. Calbe R09 has a pH of 11.8.
The mixed developer should be left a couple of weeks before use.
Ian