In my business, there are few things sadder than seeing a valuable autographed item that's been ruined by being displayed or stored improperly. I know, because I've damaged a few myself.
By far, the biggest threat to an autograph is ultraviolet light (UV). Sunlight and fluorescent lights both emit UV. You can't see UV but you can certainly see what it does. Have you ever seen a rolled up newspaper left out on a driveway for a couple days? It's probably turned a light shade of yellow, the edges and corners have curled and the paper has become wrinkled and maybe even a bit brittle. Now, newspapers are printed on low quality paper called newsprint because they're not meant to be read after a week or two at the most. But the fast deterioration of newspaper shows how powerful UV can be.
Maybe you've been to a sports bar with autographed memorabilia displayed near exterior windows or under fluorescent lights. Chances are, whatever autographs were closest to these UV sources have faded or even almost disappeared. Needless to say, whatever value these items had has diminished tremendously. Even non-autographed paper memorabilia such as cards, magazines, photos and programs will suffer bleaching from UV.
What can you do to prevent this from happening to your prized collectibles? It's pretty simple. Keep your autographs and paper collectibles out of direct sunlight and far away from fluorescent light.
Even limited exposure to direct sunlight or fluorescent light will eventually fade autographs on any items, especially those signed in black or blue ink.
Even keeping the item in an acrylic display case or framing it in glass will not protect it from UV. There are some cases with UV protection (AutographsForSale.com offers cases both with and without UV protection
), and you can ask your custom framer to use UV protective glass (more expensive). But even so, no UV protection is 100% effective, and some studies have shown that UV protection is greatly overstated by the manufacturers. Therefore, it's always a good idea to keep even UV protected items away from direct sunlight and fluorescent light.
Now, you don't have to store your autographs and paper collectibles in a dark closet 24 hours a day. It's OK to take them out every so often, just don't leave them exposed to UV for extended periods of time.