[Kerik]

Hmm, is there a danger the wet plate may dry out before the exposure is finished?

I would think so. Collodion is very slow. Today I was making tins and ambros under overcast and intermittent sun. My exposures were about 20-25 sec at f/11. If you exrapolate that out to pinhole sized f/stops and throw in some time for reciprocity, you'd end up with very long exposures and very dry plates.

Kerik
www.kerik.com