Fading Ink on Book Covers: Sunlight Cause?

[Gringo123]

I have a book with a green cover. I left it on a window sill in direct sunlight for about a week and now the colour on the exposed side has clearly faded. Why does this happen? Is it something to do with the Ultra Violet properties of sunlight destroying the pignments in the ink?

 

[Andy Resnick]

That's my understanding: the UV radiation chemically breaks apart the dye molecules.

http://www.oddparts.com/ink/faq19.htm

 

[DaveC426913]

BTW, I have noticed that the yellow/green dyes commonly used are particularly prone to fading.

If you look at signs is shop windows, they are almost invariably magenta/blue-biased as they fade. This means that magenta's and blue's complementary colours - green and yellow - are fading first.