Quote Originally Posted by Roger Cole View Post
There are several versions on the market, and other threads here about that. Some are older formulations of the the Rodinal formula and some newer ones.
No there are only 2 versions on the market.

Genuine Agfa Rodinal as made fom the mid 1960's when the formula was changed at the time of Agfa's merger with Gevaert. This has an excess of Hydroxide and a higher pH and is now sold as Adonal, Blazinal. RO9 One shot etc but it's all made by the same factory.

Then there's the former Agfa Orwo version made by Calbe which uses a pre WWII Agfa formula, has a higher p-Aminophenol content but no free hydroxide and so a lower pH. this is sold as Calbe RO9, APH09.

The problem is that the two versions don't behave quite the same. many German and Continental EU photographers prefer the older version which is why people like Mirko ant Fotoimpex sell and distribute both.