A technique some painters use is to first paint a base layer in a complementary color, or a different temperature -- e.g a cool blue or green base layer versus a warm red on top.

It's a convenient way to get more vibrant looking colors, since depending on the opacity of the second layer you get different levels of saturation and color contrast.

It would be funny if some sculptures use this method and the reconstructions are only based on the bottom layer and turn out to be the exact opposite of what they actually looked like.