2 years back I went for the Mona Lisa exhibition that took place in Singapore. It was a whole exhibition and when we reached the end of the exhibition, we saw a duplicate version of the original painting.
The room was dark to prevent any form of de-colorizing of the painting. However, there is a spotlight that shines on the painting once on awhile.
I like how the light shone from above. We are able to see the colors of the frame and due the shadows formed, it gives the painting sort of a mysterious feel.