SA: How do you study paintings?
AS: Our process starts with close looking, often with a microscope. When we look at the painting, we might see what’s on the surface. But there are things hidden beyond the surface, and that’s where technology becomes really useful. Once we have done an examination with natural light, we might turn to other regions of the electromagnetic spectrum: X-rays, ultraviolet light, and infrared light.
SA: What new information can those technologies reveal?
AS: X-rays can show the kind of canvas the artist used, how much damage is on the painting, and even if an artist reused a canvas. Infrared light penetrates the paint layers. The underdrawing, which is the preparatory sketch the artist used to guide the painting process, becomes visible. Ultraviolet light helps us distinguish between materials that might have been added during a previous restoration effort and the original materials.