“How beautiful yellow is!” Vincent van Gogh wrote in an 1888 letter to brother Theo van Gogh that began “Sunshine, a light which, for want of a better word I can only call yellow—pale sulfur yellow, ...

Learning to name the colors is a ritual of childhood. At first kids have no clue; often they'll just say everything is "boo." Pretty soon, though, they can rattle off Roy G. Biv with aplomb. Still, ...