I was planning on running a test on GardenCast to see how it held up outdoors, but it didn't last. I was marbling paper, and just had to find out if it'd take on raw plaster. This piece being handy, I tried it out.

It's pretty pale and pretty blurred, but I think that's because plaster doesn't accept the paint as well as prepared paper, so it lost color and detail when getting rinsed.

This fellow somehow lost track of what he was doing and opened his eyes after I'd gotten alginate over them. He complained afterwards that his eyes were tearing a lot, but they weren't red, and he swore up and down that he hadn't opened them. Until, of course, he saw the cast.
Detail of the right eye. I took this upside down with repect to the light, so the shadows will look a bit awkward; sorry.
Detail of the left eye.