Help! The sun is bleaching my books!

The sun comes through the windows in my apartment in the morning and afternoon and hits several bookshelves. Several of my spines are already bleached, a few fronts of more promenently displayed books too. Weirdly not all, which I say speaks more to the quality of some printers' inks…

I really don't want to have curtains covering all my windows. I'm in here too much to make it feel that much like a cave. So I need better choices.

I know there are films you can put over your windows, has anyone had luck with that? Or are there any better options? Are there dust jackets I can make to put on them that will do what I need (I don't want to put them on every book, I have a lot, but I will)?

Thanks for any tips anyone might have!