It’s not to often that a conservation treatment reveals a much less appealing person beneath! Usually previous restoration campaigns are unrefined and blatantly obvious, and the final conservation treatment is a beauty to reveal. While the above painting’s restoration (right) was quite sweet, the original (left) is much harsher - but accurate to the time it was created. A 130 years ago British restorer, Francis Leedham, transferred the original portrait from its panel support to a canvas support and heavily overpainted the surface to create a more sellable product.
To read more about the recent conservation of this portrait of Isabella de Medici - attributed to a follower of Alessandro Allori, in 1574 - at the Carnegie Museum of Art, here: http://www.theartnewspaper.com/articles/Not-fake-but-tarted-up/32874