Ambrotype. Check out some of the alt-process links. The book Coming Into Focus edited by John Barnier has a chapter on it. Also, I think Keepers of Light by Crawford had some info on it.
I remember an article about this in Black and white photography a while ago, the photographer was a woman who went round the cattle ranches in the states and made these wetplates in a huge box camera. I seem to recall that they were tin-types. I could be wrong but, i will try to find the magazine to check.
The wetplate process utilizes ether and collodion (guncotton dissolved in ether and grain alcohol) which are extremely flammable with explosive fumes and byproducts. Some hardcore wetplaters also use potassium cyanide for the fixer although plain hypo can be used for that purpose. The cyanide is lethal if mishandled. There are some other nasties as well but these are the most dangerous. Not like working with X-Tol...
And you do need some sort of darkroom. Here's what I use: