Quote Originally Posted by piu58 View Post
Rodinal does not like A) high temperature and B) overdevelopment. I use Rodinal at 16 deg Celsius which requires to increase the dev time by a factor 1.6.
It is a good idea not to try receiving the box speed of the film because that leads mostly to overdevelopment.
With that in mind you can get a quite fine grain from Rodinal. Other devs can give slightly finder grain, but the grain itself is muddy.
That's the misconception about Rodinal it's not the temperature of the deveoper itself that causes any problems it's poor temperature control throughout the entire process cycle including the washing.

By working at a lower temperature you're reducing the swelling & softening of the emulsion slightly but it's entirely unecessary if you just monitor all stages of the processing and keep temperatures within +/- 1? C of the initial developer temperature.

I used Rodinal as one of my two main film developers for about 20 years and working at the recommended 20? C was never an issue.