Originally Posted by mono
Go with 1:50 and lower temperatures.
HP5+, 400 ASA, 23 min at 16 C.
There is an article (http://home.arcor.de/piu58/fotoweb/a...ze/Rodinal.pdf) about Rodinal development with lower temperatures, but only in German.
That is from me. If you have any questions do not hestiate to ask.
For short: Use Rodinal at 16°C, with longer development time. The factor is around 1.6.