What with the brutal Arizona sun, thank the moon for Phoenix museums. From the Arizona Science Center to the Phoenix Art Museum, the region’s air-conditioned exhibit halls are not only among the most educational things to do in Phoenix—they’re also some of the coolest. Staying cool is just one benefit, though, of staying out of the blistering sun. That environment is also what allows paintings and other documents to stay preserved for generations. In other words, the same UV rays that harm your skin can also ruin works of art. Learn how framers keep rays from stealing artwork's shine with our look at UV glass.

Even Portraits Can Get Sunburned

If left unprotected in the sun, works of art—especially paper works such as pastels, prints, photographs, and watercolors—will fade and, over time, even begin to fall apart.

You might think artwork hung indoors would be adequately protected from the invisible part of the light spectrum that causes sunburns. But all visible natural and electric light, indoors and out, comes packaged with UV radiation that eventually begins to break down a piece. (Bonus Points: Conservationists have even speculated that the Declaration of Independence has deteriorated over time from the light of camera flashes.)

How Museums Keep Art Safe

All glass will block some UV radiation, but museums and galleries choose glass that's been coated with a UV-resistant substance. This is usually accomplished by being baked onto the surface or chemically deposited.

Anti-UV coatings—just like sunscreen ingredients—work in one of two ways: by absorbing the rays before they reach the artwork or by reflecting them back. They do this by changing the surface of the glass, endowing it with a new microtexture via a material whose molecules are arranged to take in the radiation's energy (in the case of silica, a common coating) or to bounce it right back.

Potential Drawbacks

Some UV coatings can give off a greenish or yellowish tinge, though museum-quality glass is typically made from a special low-iron formulation for maximal clarity. UV-coated glass can also be more vulnerable to scratching or other superficial damage, depending on the coating method used. Besides glass, another option is specially formulated clear acrylic, or Plexiglas, where the UV-blocking agent is mixed right into the plastic. The enhanced durability is especially useful if you're framing a larger work or do a lot of indoor batting practice at home.