Rodinal recipe

Solution A
Water, 125F/52C 750 ml
p-Aminophenol Hydrochloride 100 g
Potassium Metabisulfite 300 g
Cold water to make 1L

Solution B
Cold Water 300 ml
Sodium Hydroxide 200 g
Cold water to make 1L

Mixing instructions: Add chemicals in specified sequence. Always use cold water when mixing sodium hydroxide due to risk of heat reaction. Unlike many other two part developers, you must mix both parts together to make the concentrated solution.

Allow Solution A to cool until a precipitate forms. Mix Solution A in an iced water bath at this stage, then slowly mix in Solution B while constantly stirring, first adding 280ml of solution B, and then adding the remainder until the solution suddenly turns dark. Follow this by adding the last drops of Solution B very slowly.