>The process of re-attribution isn't a very forensic one: there's no
>paint chip, no artistic DNA that can be compared, to solve the
>authorship question. While the type of tack used to stretch a canvas
>might be a hard clue to authorship, mostly, the process relies on an
>examination and assessment of "artistic values."
Cool art history pertinent to this:
"...such a study may help us to break out of the fruitless opposition between "rationalism" and "irrationalism.":
http://www.cch.kcl.ac.uk/legacy/teaching/av1012/Ginzburg,%20Clues.pdf