How Do UV Filters Work in Picture Frames?

Written by Mark Rogers

Light is artwork’s greatest friend, allowing us to view and appreciate art, but it is also its greatest foe: it can cause serious, irreversible damage to any type of unprotected artwork. The glass and art preservation industries have developed countless products to protect these precious pieces from light while still allowing us to display art, including UV-filtering glass.

What Is UV Light?

UV light is part of the electromagnetic spectrum, of which visible light (i.e. the light we can see) is also part. We cannot see UV light, and it features shorter wavelengths than visible light and therefore more energy.

This powerful light breaks down the chemical bonds that allow us to see the color of an object, which causes the color to fade. This is only one outcome of photodegradation, the term for damage caused by light; others include embrittlement, yellowing and disintegration. Artwork is particularly susceptible to photodegradation, considering it often uses materials that are quickly damaged by light such as dye and paper.

Protecting Against UV Light: Picture Frames

Standard glass (most commonly soda lime glass, which is used for both windows and picture frame glazing) actually provides some UV protection, absorbing about 97% of UVB rays; however, UVA rays, which also cause damage, can still penetrate the glass.

To qualify as “providing UV protection” by the Professional Picture Framers Association (PPFA), the UV filter must be able to block at least 97% of all UV rays, including UVA and UVB. There is no single method to ensure that picture framing glass protects against UV light, and different manufacturers of glass have come up with their own proprietary coatings and techniques.

Laminated glass, a type of safety glass used commonly for car windshields, is like a glass sandwich: it uses sheets of glass with an interlayer made of various materials, most commonly polyvinyl butyral (PVB). According to one study, this type of laminated glass completely blocks both UVA and UVB radiation. Laminated glass is less common in picture framing due to its considerable weight and cost, but there are certain manufacturers such as Tru-Vue that carry this type of glass for particularly valuable items.

Other types of UV glass feature a special coating that either filters, or blocks, the UV light or absorbs the UV light. A coating that filters UV light does not allow UV rays to enter the glass, while UV filters that absorb light effectively “trap” it before it gets to the artwork underneath. Artglass, for example, uses a UV-blocking molecular film that blocks over 90% of UV light, depending on the model. UV protection on glass use coatings like the above; with UV-filtering acrylic, the protection is built in.

Frame Destination carries several types of UV-filtering glazing:

Neither is “better” than the other, and the quality of the framing glass depends on many more factors than the mechanism of UV filtering, such as its clarity and any anti-reflective properties. The only surefire way to protect artwork from UV light is to store it in archival photo storage boxes and display a framed copy, as even glazing that filters 99% of UV light cannot completely stop degradation.

To best protect your possessions but still display your artwork, choose a suitable UV-filter glass and rotate out the pieces you display every few months, making sure that no paintings, prints and photographs are hanging in direct sunlight.

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