First of all, color sets work on Red, Green, Blue, Transparent. I believe 1.000 is the max and 0.000 is the minimum, meaning that instead of hues (I might get some terminology wrong, I don't have photoshop open.) or 0-255, it works on a percentage.
Meaning 255 255 255 1 would become 1.000 1.000 1.000 1.000, or white.
.500 .500 .500 1.000 would be half black, half white.
So on and so forth.