Macroscale multimodal imaging revealed the use of lead white in ancient painting production technology in Greco-Roman Egypt

X-ray fluorescence elemental maps of the sum of the K or L lines for Iron (Fe), Lead (Pb), Calcium (Ca), Potassium (K), and copper (Cu). X-ray fluorescence is the emission of characteristic "secondary" (or fluorescent) x-rays from a material that has been bombarded with high-energy x-rays or gamma rays. Each element has a unique set of energy levels and emits a pattern of x-rays characteristic of the element with an intensity proportional to the concentration of the corresponding element. (Source: Delaney JK, Dooley KA, Radpour R, Kakoulli I. Macroscale multimodal imaging reveals ancient painting production technology and the vogue in Greco-Roman Egypt. Sci Rep 2017;7[1]:15509. Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)