What color to paint a hive?

I bumped into a video suggesting that each hive be painted a different color to make it easier for bees to find their hive.  I have never heard of this being a problem.  Opinions?

I think it is more of an issue with large apiaries with many hives close together. They say that putting different patterns on each hive also helps.

The wood color is the best color. it may not be attractive, but since bees attract to build their hive at trees.