the.com/indigo blue
the color between us and ultraviolet, smuggled into rainbows by a man who really liked the number seven
newton's choiceAdded to the spectrum to match seven musical notes
slave cropIndigo dye fueled colonial plantation economies for centuries
hard to seeMost humans struggle to distinguish it from blue
denim originIndigo dyed the first blue jeans worldwide
oldest dyeUsed over six thousand years ago in Peru