are anaglyphs red/green or red/cyan?

[michaelrepucci]

Oh, an elegantly simple solution indeed.

I'm not sure what I could do with a post-process shader, but if I could change the background color without effecting the color of the anaglyphic objects in the scene, then I could put a very faint reddish-cyanish-brown color in the background which would look perceptually like the red (cyan) ghost image that is showing up through my cyan (red) filter. This would make the ghost perceptually invisible. Unfortunately, when I change the background color, it alters the colors of the anaglyphs, since it too must be put through the color mask. I gather I can't selectively activate certain objects as anaglyphs, or is that what I can do with a shader?