There's no evidence that using Rodinal at different temperatures has any effect on the grain size in a negative. However the hydroxide in Rodinal can have a softening effect on the surface of the emulsion causing micro reticulation, this only occurs when temperature variations are excessive during processing and is more likely to happen at higher temperatures. The results is prints with more apparent graininess.
Rodinal has always been diluted, I posted the pre-WWI instructions here on APUg, and by 1907 other companies wre making similar p-Aminophenol concentratrated developers, like Ilfor Certinal, I'm not sure when Kodak introduced Kodinol but it was before WWII (it was never made or sold in the US).
Last edited by Ian Grant; 05-29-2013 at 05:00 AM. Click to view previous post history.