I've got dark, mirrored UV film because it had the best UV rating for whatever brand I chose, but they do make clear (or at least clearer) films. IMO it's kind of a pain in the ass to install and you can tell it's DIY and not a perfect slate mirror finish so consider a professional if this window is the focus of the room.
UV film helps but doesn't prevent fade. This was a test on Pinside with construction paper for a month with no film, Gila "up to 99%" UV film, and a control placed in the dark. Curtains are still the gold standard if you're trying to prevent fade: