I'm attending some of the sessions of the "A Space Odyssey: Storage Strategies for Cultural Collections" conference here at MHS and one of the presenters this morning (James Reily from IPI) gave us a link to this quick online dew-point/RH/Temp calculator.

http://dpcalc.org/

Thought some of you might enjoy it, especially if you are trying to convince someone or other to change storage conditions.

Jason