Today, the mystery of red dye. The University of Houston presents this series about the machines that make our civilization run, and the people whose ingenuity created them.
When Hernan Cortez met Moctezuma in 1519, the Spanish conquistador was impressed by the Aztec leader's brilliant red robes. In Europe, the color red was associated with royalty and power due largely to how hard it was to find a good source of red dye.
Moctezuma Xocoyotzin
Photo Credit: Wikipedia.
Cortez learned that the Aztec's red dye was called cochineal, and he sent some samples of it back to Spain. It was a huge success. The Spanish king Charles V had massive debts to pay in order to keep his empire running. Cochineal became one of Spain's most valuable imports, and they kept its source a closely guarded secret.
But Spain didn't have enough skilled textile workers to satisfy the European demand for red fabrics. Spanish merchants sold the dry cochineal grains to overseas dyers. The Venetians had a reputation for producing the highest quality dyed garments, but even they could not discern what exactly cochineal was. Some claimed it came from a seed; others thought it was some sort of animal product.
The mystery was finally solved by a Dutch draper named Antonie van Leeuwenhoek in 1687 who tinkered with small glass spheres that allowed him to see the fine details of thread more clearly. Having invented one of the first microscopes, his curiosity wasn't satisfied by looking only at fabrics. Van Leeuwenhoek examined pond water, wood, blood-- and raw cochineal. He revealed that the coveted dye came from a surprising source: an insect.
Anthonie van Leeuwenhoek
Photo Credit: Wikipedia.
The insect was given a scientific name: Dactylopius coccus, a type of scale bug that lives exclusively on prickly pear cactus. Mature female cochineal bugs are wingless, with tiny legs that make them almost immobile. Unable to escape from predators, they instead produce a chemical defense-- carminic acid-- the source of cochineal's deep scarlet hue.
Dactylopius coccus
Photo Credit: Wikipedia.
Some of the bugs were smuggled out of Mexico and soon there were cochineal farms in Algeria, India, Brazil, and Peru. Cochineal dye soon became more widely available. It was used as paint by artists like Rembrandt. Cochineal provided the color for the British military's famous red coats as well as the iconic red stripes on The Star-Spangled Banner.
Today cochineal is still used to produce a natural dye known as carmine red, Natural Red 4, or E120 used not only for fabrics but also in food and cosmetics.
Carmine red is being used as a dye for microscopy in this image.
Photo Credit: Wikipedia.
Another modern use for cochineal is ironic given its history. Cochineal-based dyes are used as a stain for making cellular structures visible under a microscope. The lenses used in today's microscopes have come a long way from the simple glass spheres invented by van Leeuwenhoek, but the dye still comes from the same insect source.
I'm Scott Solomon, for the University of Houston, and interested in the way inventive minds work.
Greenfield, A. B. (2006). A Perfect red: Empire, Espionage and the Quest for the Colour of Desire. Random House.
https://www.britannica.com/technology/cochineal.
https://www.businessinsider.com/how-cochineal-insects-color-your-food-and-drinks/.
https://www.wired.com/2015/09/cochineal-bug-feature/.
See Episode No. 3193.
This episode was first aired on June 29, 2021