Singing the blues

Our early ancestors had a fondness for red. Their prehistoric cave paintings are absolutely flush with bright scarlets and deep burgundies. Almost 95 percent of all surviving pigments from the African Stone Age are made from iron-rich red ochre—mixed with rendered animal fat or human saliva to make a sticky paste—laboriously excavated, centrally processed, and widely distributed as what might have been mankind’s first internationally traded commodity. And it was invariably used to represent the human form, the obvious symbolism of all these sanguine hues remaining something of a cultural constant across our varied evolution. But if the early manufacture and trade of pigments emerged in part to satisfy man’s need for aesthetic self-expression, his burgeoning capacity to conceptualize himself through art was as much shaped by the available materials. The vibrant crimson dyes of Mesoamerica were...