On: Ultraviolet light reveals how ancient Greek statue...

[sown]

I wonder if there was certain lightning requirements.

For example, the famous bust of Abraham Lincoln requires light over head and behind it to give it a serious, solemn almost brooding and suffering look

http://farm4.static.flickr.com/3504/3753443355_6ed82e886f.jp...

In full light, though, it looks less impressive.