Read an interesting article in an Astronomy magazine the other day that pertains a bit to this. It was explaining how there is no definitive black or white. The color you see is a combination of the reflected light frequency verses the intensity of the background. Go to a strong enough extreme on the intensity of the background and white can appear black and vise-versa.
For example, the natural color of the surface of the moon is similar to a dark asphalt. However, when you see it in the sky, lit up by the powerful light from the sun against the black background of space, it can appear very white.
Another example is a sunspot. A sunspot is a cooler spot on the surface of the sun. Cool is a relative thing of course. At an average temperature of 3000–4500 K, you know damn well that a sunspot is going to be blindingly bright on it's own. However, when photographed against the 5700 K of the rest of the suns surface, they appear as black.
