French scientists have shone new light on the painting technique that allowed Renaissance master Leonardo da Vinci to give the Mona Lisa such an extraordinary delicate charm.
Working with an X-ray scanner, scholars at the Louvre were able to detect each layer of glaze, paint and pigment in seven of Leonardo’s masterpieces, and reconstruct his painstaking shading technique, known as "sfumato".
"Minute observations, optical measurements and reconstitutions have already described the 'sfumato', but new analysis can confirm the procedure of this technique," said a statement from the state CNRS research institute.
One of the reasons why the Mona Lisa remains renowned to this day as a great portrait is the lifelike shadows and tonnes that give her enigmatically smiling face a sense of depth and reality.
According to the scientists, the shadows were built up by dozens of translucent layers of glaze. Each layer was only one of two micrometres thick, but each contained a carefully dosed amount of pigmentation.
This was a new technique in the Renaissance, and part of the reason Leonardo and his contemporaries were able to make what had been the once flat images of the Middle Ages appear to leap from their frames into photo-like reality.