What is the origin of surnames based on color?

I understand the background of names such as Baker, Carver and Hammer but, what are the origins of names such as Black, Blue, Brown, Green and White? Are they based on some common structure or do they each have their own twisted tale?

Solution 1:

It looks like some are related to physical appearance:

• Black supposedly relates to hair color.
• Green had a pretty colorful history. It supposedly referred to anyone who liked green, played the Green Man in the May day parade, etc.
• White was someone with white hair or a pale complexion.

Again, most of them seemed to harp on some element of physical appearance.