The August 10th Proceedings of the National Academy of Sciences was filled with science and art discoveries.
Marco Leona of the Metropolitan Museum of Art in New York was able to analyze the color of a fragment of leather from an ancient Egyptian quiver. The discovery that the color was madder, a red dye, is the earliest evidence for the complex chemical knowledge needed to extract the dye from a plant and turn it into a pigment, Leona reports. This means that four thousand years ago Egyptians had already mastered the process of making madder.
The find is some 700 years earlier than any previously known use of madder, which became highly popular in the Middle Ages and provides many of the red shades and glazes in the work of the Dutch painter Johannes Vermeer.
“Tracing the use of organic colorants offers a way to follow trade routes, identify relations among archaeological objects, detect forgeries and attribute works of art,” Leona wrote.
Leona refined a technique called Raman spectroscopy, which relies on the scattering of light to study materials. That process is not generally suitable for studying madder or some other dyes, but Leona enhanced the result using tiny metal particles that could amplify the findings and detect even very low levels of chemicals.
In addition to tracing madder, he was able to identify as kermes the red in the painting “St. John the Baptist Bearing Witness,” from the workshop of Francesco Granacci in the early 1500s in Florence, Italy. Kermes was a dye made from the bodies of insects and was common in Europe before the importation of cochineal from the New World.
And the red color in the Morgan Madonna, dated at between 1150 and 1210, turned out to be based on lac dye, which originated in Asia and may have been imported to southern Europe by Muslim traders.
This is the first documented example of lac dye in European art before the 15th century, according to Leona. He noted that this sculpture was originally housed in the French region Auvergne, which borders Provence, where commercial records from a few decades later record importation of lac. The French artist who created this wooden sculpture may have been one of the first Europeans to use Lac, an insect-derived pigment.
Art historians knew that the dark red dye, extracted from a resin that the tiny lac insect (Kerria lacca) secretes onto trees to protect itself, was popular in 15th-century Renaissance art, but the Morgan Madonna pre-dates those pieces by about 3 centuries. Leona identified the dye from a 25-micron-wide glaze sample about half the thickness of a human hair. Art historians believe that Lac may have arrived in Europe from India through North African traders.