A painting can tell you a lot about the subject, the artist and the time and place it was made. Sometimes, they seem like perfect windows into another world. But what about how they were made? A painting is meant to be seen as a finished product, and the process of their creation is largely lost. Now, thanks to x-rays, multi-spectral imaging and laser scanning, we can see a painting's past. The revisions, mistakes and edits are revelaed. Because of that, sometimes some interesting history is discovered as well. Isabella Medici gets a makeover. Carnegie Museum of Art Because of...