This plain paper folder was placed in a window with southern exposure at the Alaska State Museum for two months. The far left side was covered with aluminum foil to block out all light. The middle third was covered with UV filtering plastic film. This film was tested with a UV light meter to insure it was effective at blocking ultraviolet light. The far right hand side of the paper folder was left completely exposed.
On my computer monitor (and on the real folder) you can see a slight difference in the faded blue color between unfiltered and filtered, but both are drastically faded from the section that was not exposed to light at all. Hopefully this is evident on your computer monitor as well.
While filtering UV light does eliminate a dangerous wavelength of light that is contributing to deterioration beyond just fading, if you seek to prevent the visual change of your colors from light fading, UV filtering will not give you the protection you need. All light is damaging, and fading is cumulative and irreversible. To prolong the vividness of colors, you must bring light levels down and limit overall exposure, not merely filter for UV light.