Wet plate collodion on glass.
About 12 years ago I was out for a walk and encountered a dumpster someone had next to their driveway - it seemed they were moving and clearing out a lifetime's worth of junk. maybe 2/3 of the dumpster was filled with brown paper boxes about the size of a single shoe, and curiosity led me to open one to see what it contained. Inside were plaster casts of teeth! There had to have been thousands of these in the dumpster. I salvaged a couple boxes of them, and to this day I regret not going back and salvaging 50 or 60 more boxes of them. They are exquisitely made, and some have a very soapy glossy finish to them. They feel really nice to touch. Creepy, huh?
2:30 second exposure at f11.5 with Coffer's #7 for negatives. Developed in well-seasoned Iron sulfate neg developer.