Haints are ghosts, wraiths, disembodied spirits, etc. Never heard they were a color, though!!
Using housepaint as a sort of totem is popular in Amish country--barns often have large icons painted on them as wards. This is also a strongbelief amongst African tribes and their offshoots in the Caribbean.

So maybe its not the color of the haint, but the color used to ward him off.

A