During my recent trip to Paris, I took the following picture of the Mona Lisa by Leonardo da Vinci:
This looks pretty crappy with the yellow color from the lights and a few reflections. This happens sometimes when you can't take your time or bring lots of you own equipment. The low light and the crowds made getting even a sharp picture a small feat.
But all is not lost. Open the picture in Photoshop, adjust the levels and color and edit the spots out and you get this:
Now that is more like it.