The Color of the Future: A history of blue

Summary

La Gare Saint-Lazare, arrivée d'un train, by Claude Monet (1877)My favorite color has changed throughout my life, cycling through the entire spectrum of visible light and beyond. I don’t remember when blue was the chosen one, exactly; maybe when I was 13 or so. After that, yellow, purple, orange, green, and pink occupied the top spot for various periods. Blue never made a comeback. I saw it as a banal, common color. After all, the sky is made of it, and the sky is everywhere. Then I realized when compiling the tech tree that blue is the most fascinating color, because it is the hardest of the common colors to create artificially. You can’t just take a piece of the sky and put it into a painting. And blue pigments are fairly rare in minerals, plants, and animals. So blue had to be invented, time and time again, from 4000 BC to the 21st century. It is the most technological color, and I’m willing to claim that this is why it is usually, in science fiction and elsewhere, used to represent the future.The story of blue starts with indigo. It is an organic dye made from plants in the Indigofera genus, which grow throughout the tropical and subtropical regions of the world. The first known traces of indigo dye come from the New World, in ancient Peru, 6,000 years ago, using Indigofera suffruticosa, or anil. In the Old World, it was known from Africa to East Asia, but became particularly associated with India (hence indi-go), where Indigofera tinctoria was domesticated. Indigo soon became a luxury, traded from India to Greco-Roman and then medieval Europe, where the same blue dye could only be made from a less productive plant, woad or Isatis tinctoria. Eventually the “blue gold” became an important colonial crop in the Caribbean and was part of the story of slavery, next to sugar, tobacco, and cotton. A bucket of indigo in China (source)Before indigo was a thing in the Old World (that started circa 2400 BC), the Egyptians had already become obsessed with the color blue. Be...