Quote Originally Posted by mnemosyne View Post
While it might not do any harm with Rodinal, I would generally advise against shaking developers, as it will introduce oxygen into the solution, which will have a negative impact on the life expectancy of most developing agents.
I also don't shake my Rodinal ever as sometimes it does crystallize. Those crystals do not dissolve from the shaking so you end up having crystals on your film. I just use whatever's left without the crystals, works fine