Here is an interesting thread on Reddit, where people explain why black, white, brown turned into last names, and there are no surnames like orange, purple, etc: reddit.com/r/AskHistorians/comments/3xi7am/how_did_last_names_of_colors_arise_blue_green/ In the comment section, you can find a user with...

Mr.Philip Hudson
I suppose that gentleman post a message just to promote the service he is linking to in his signature.