More optics experiments - today I achieved visual negation! Starting with a yellow square painted on the wall, I then projected a violet square on top of it (which looks blue in the video). The resulting color mixture yields a gray-green (which looks positively pea green in the video. slightly less so in real life, though still not as gray as I'd like... stupid color calibrations). I then matched that optical color with the color to be projected as a background.
The result: the yellow square disappears into the background. Check it out!
After an excellent studio visit with projection mapping guru John Ensor Parker, I'm psyched to continue exploring these projection possibilities!