Andrew, I think your comment about red becoming black is exactly why it works in muddy water.

In low light conditions, you want a darker bait to provide a greater profile.

Something I've never really understood though is this, if the light penetration is really low, once you get beyond the light, everything is "invisible" so at that point color won't matter at all. As long as there is some light for you to shilouette against, then darker colors will provide that best shilouette, I believe. And on another note, how badly did I spell that word, shilouette?? ha ha

Danny