Scientists winkle a secret from ‘Mona Lisa’ about how it was painted

Scientists using X-rays have discovered that Leonardo da Vinci used a different oil-paint recipe for the “Mona Lisa” than for his other paintings. The researchers found a rare compound called plumbonacrite in the first layer of paint, confirming that Leonardo most likely used lead oxide powder to thicken and help dry his paint. This discovery highlights Leonardo’s experimental nature as a painter and adds to his timeless and modern reputation.