For those interested in DaVinci's techniques

[Tsa'räni]

"X-ray fluorescence spectroscopy unveils Da Vinci's astounding sfumato technique"

http://www.physorg.com/news200721901.html

In short, they've come up with a way to analyze the individual pigment layers, rather than all of them as a whole.  They can see what each layer was composed of, how thick it was, etc.  It's a pretty amazing insight into his techniques.

[Nyx]

Hmm.. no wonder it took him so long to finish some paintings. Interesting how the technique can be so precise that they see each layer on its own. And maybe it's just because I'm a child of the computer age, but this makes me think of layers in photoshop. Except, he couldn't go back and change underlying layers...