Haint Blue

I just found out about this. Allegedly among various Southern peoples the belief exists that various shades of blue can repel ghosts. From Curious Expeditions:

http://curiousexpeditions.org/?p=722

Bright Prussian blues, pasty greens, muted periwinkles, rich aquas and pale violetshttp://curiousexpeditions.org.nyud.net/http://curiousexpeditions.org.nyud.net/; yet they are all one color, united by a name and an ancient tradition.
Haint Blue originated in the deep American South. Today, in cities and towns throughout the south, one will find these blues and greens tints on shutters, doors, porch ceilings and windowsills, gracing many historic homes. The pretty blues and greens compliment any grand old Victorian mansion, but the first painted strokes of Haint Blue adorned not the homes of the rich, but the simple shacks of African slaves.