Short answer
It removes one important cause of damage, but not the main cause of fading. UV-filtering glazing and films cut ultraviolet — which yellows, weakens and chalks materials and contributes to fading — by roughly 80–99% depending on the product, and bring daylight close to the traditional 75 µW/lm museum limit. Visible light still fades sensitive colours, so filtering must go with lower light levels and shorter exposure.
Ultraviolet is invisible and adds nothing to how well we see, so removing it costs nothing visually. Sources differ greatly in how much they emit per unit of visible light. The Canadian Conservation Institute gives ordinary incandescent lamps about 75 µW/lm — the value adopted as the traditional museum limit — and daylight through window glass about 400–500 µW/lm. Phosphor-converted white LEDs emit very little UV, which is one reason they are favoured in galleries. Fluorescent lamps vary and were a major source in older displays. Because a window is often the largest UV source in a room, filtering daylight usually achieves more than changing lamps; CCI notes that good filters can bring levels to around 40 µW/lm or lower.
CCI's measurements show large differences between materials. Ordinary glass removes only about a quarter of UV. Museum-grade UV-filtering glass removed on average 83%, with wide variation between products (± 14%). UV-filtering window films averaged 96% ± 2% over 300–400 nm, and conservation-grade UV-filtering acrylic 99% ± 1%. The table applies those reductions to daylight through a window. Filters age: CCI expects applied films to last 10–15 years indoors, less in sun and heat, and found films up to 5% less efficient than claimed, so it recommends checking transmission data before buying and measuring UV every few years. Only the best materials reliably reach the traditional limit when daylight is the source.
For framed works on paper, both glass and acrylic are available with UV filtering. Glass is rigid, scratch-resistant and hardly picks up static; acrylic is lighter and safer for large works and travel but readily holds an electrostatic charge. CCI warns that this charge can lift flaking paint or loose particles, making acrylic unsuitable directly over pastel, charcoal and chalk unless spacing is increased. Anti-reflective products reduce glare, which improves how colours are seen through the glazing, and some can sit at a distance from the work. None removes all UV, and none reduces visible light, so glazing slows yellowing and UV-driven fading while the work can still fade from the light that lets you see it.
Infrared is the other invisible band. It does not drive the photochemistry that fades colour — CCI notes that infrared photons are not energetic enough — but it heats whatever absorbs it. Under strong incandescent lighting or direct sun, surfaces can reach 40 °C above room temperature, and CCI estimates thermal decay rates can rise twentyfold or more. Warm glazed frames in sunlight also create damp microclimates as temperature cycles. LED lighting and keeping works out of direct sun avoid most of this. For fading itself the order of priorities is: keep direct sun off sensitive objects, reduce visible light and hours, then remove UV — not the other way round.
| Added filter | CCI measured UV reduction | Estimated UV remaining | Below 75 µW/lm? |
|---|---|---|---|
| Ordinary glass (extra pane) | 26% ± 11% | 296–370 µW/lm | No |
| Museum-grade UV-filtering glass | 83% ± 14% | 68–85 µW/lm | Borderline |
| UV-filtering window film | 96% ± 2% | 16–20 µW/lm | Yes |
| Conservation-grade UV-filtering acrylic | 99% ± 1% | 4–5 µW/lm | Yes |
Why: Visible light, not UV, is the main cause of fading for sensitive colourants.
Fix: Reduce illuminance and hours, move it away from windows, or display a facsimile.
Why: Acrylic glazing's static charge lifted loose pigment.
Fix: Have it reframed with glass or with more space between work and glazing.
Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.
FactStrong evidence
CCI measured average UV reductions of 26% ± 11% for regular glass, 83% ± 14% for museum-grade glass, 96% ± 2% (300–400 nm) for UV window films and 99% ± 1% for conservation-grade acrylic.
FactStrong evidence
UV filter films are expected to last 10–15 years when applied indoors, and tested films were up to 5% less efficient than performance claims.
FactStrong evidence
Acrylic glazing readily holds an electrostatic charge that can attract flaking paint or lift particles, making it unsuitable for pastels, charcoal and chalk; no UV-filtering glazing removes all harmful UV.
Source: Glazing Materials for Framing Works on Paper — CCI Notes 11/3
Colourwise analysisModerate evidence
Applying CCI's average reductions to daylight through a window (400–500 µW/lm), only UV-filtering film and conservation acrylic reliably bring UV below 75 µW/lm; museum-grade glass averages about 68–85 µW/lm.
Based on: Colourwise calculation multiplying CCI's daylight-through-glass UV range by one minus each material's mean reduction; see the table.
Caveat: Uses mean reductions and ignores the wide product-to-product spread CCI reports.
Source: Ultraviolet Filters — CCI Notes 2/1; Agent of deterioration: light, ultraviolet and infrared
FactStrong evidence
Infrared does not initiate photochemical damage but heats absorbing surfaces; under incandescent light above 5,000 lux or direct sun, surfaces can reach 40 °C above ambient and thermal decay can accelerate by a factor of 20 or more.
Source: Agent of deterioration: light, ultraviolet and infrared
Reviewed 29 September 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.