I have seen really big grain using Rodinal and certain high speed films. Rodinal 1:25 and Kodak Recording film was like golf balls.

However, I am convinced that using a very high dilution you can actually see a finer grain when using Rodinal. I have posted a rather mundane picture in the Technical Gallery (Washing Line). Film was Tri-X and developed in Rodinal 1:100.

- Mike