This will show you what can happen to art overtime when you don't use conservation products. You can see on this mat that you can see the image and you can see it's kind of a white mat, and you can see this really horribly almost reddish dark line. Well, that's the bevel of the mat, and it would've started out looking like the bevel in this mat a long, long time ago. Nice and white and crisp. Well, this is what happens over time when it's like a paperboard or decorative board. They're going to fade. They're not going to do it overnight, they're going to do it over decades of time, but the longer they go, the worse they'll get.
This is the other thing that happens when you don't use something like a conservation type acrylic on it or glass. You can see that the picture itself is faded. This is the color of the paper originally was. It was protect underneath this mat for years and light has deteriorated this paper to just give it this really yellowing characteristic. You can see why it's beneficial to use conservation.
One final note on this subject: when you put UV glass or acrylic on your artwork, you are helping to stop the fading process, but it's not going to stop all fading. All visible light will harm your art over time. Putting UV filtered glass or acrylic on your artwork, is going to help, but it's not going to stop the problem. I have told 100's of customers that the only way to totally protect your art is to keep it in a closet. That just is not that much fun!