R09 One Shot (previously known as Rodinal) is the oldest commercially made developer available today. It is a highly concentrated acutance developer providing very sharp results. Recommended dilutions are 1:25 and 1:50 but due to its versatility, it can be mixed weaker or stronger, depending on your requirements. Generally regarded to be most suitable for slow and medium speed films but can still work perfectly with faster films.

Not to be confused with R09 Special which is a different developer.