Theater ad for one of the first commercial 3D films, Ouch, which used a subtractive anaglyph process developed by Ives and Leventhal in which two strips of film, one yellow and the other cyan, were glued together (similarlt to 2 or 3 strip technicolor). Subtractive anaglyphs are require only one projector, as opposed to the two projectors required for additive anaglyphs.