Black, it's pretty ominious right? Evil figures in stories normally wear black. Of course so does Batman and CEOs and actresses at red carpet events. How to explain that? Well, black is the absence of light, light being universally understood as good, and black being the absence of it, then it makes sense for black to be a signifier of the evil/ominous. Then again, pigment-wise, black is all the colors.
And you remember as well as I do: all the real cool kids in school always wore black. Too cool for other colors. Because black is real sleek. Black is so smooth. The first time I bought a pair of black jeans instead of the normal blue, dang did I strut my way to the check out counter. And then for a while of owning them I felt too intimidated by the implied 'cool' of black jeans to wear them. So I stuck with my blue jeans.