Science News opens a new book on an old pigment, reconstructing a botanical purple-blue hue that had puzzled medievalists for ages:
The pigment, called folium, graced the pages of medieval manuscripts. But it fell out of use, and the watercolor’s identity has eluded scientists for decades.
“We want to mimic these ancient colors to know how to … preserve them,” says Maria Melo, a conservation scientist at Universidade Nova de Lisboa in Caparica, Portugal. But to unmask folium’s identity, Melo and her team first had to find where it came from.
The researchers turned to medieval texts that described the source plant. With the help of a botanist, they discovered Chrozophora tinctoria, a tiny herb with silvery-green foliage. In a village in the south of Portugal, the team found the wild plant growing along the roadside and in fields after harvest. Back in the lab, researchers extracted the pigment from its pebble-sized fruits by following directions detailed in the medieval manuscripts. “It was really great fun to recover these recipes,” Melo says.
You can read the researchers’ study here.