News Chemistry

Ancient recipes led scientists to a long-lost natural blue

Medieval texts and modern techniques helped unveil the blue watercolor’s identity

fruit from the plant Chrozophora tinctoria

Medieval recipes instructed scientists to prepare the blue watercolor from the fruits of Chrozophora tinctoria. That provided enough dye to reveal its structure using a suite of chemical analysis techniques.

Paula Nabais/NOVA Univ.

By Carolyn Wilke

Scientists have resurrected a purple-blue hue whose botanical origin had been lost to time.

The pigment, called folium, graced the pages of medieval manuscripts.