LED lighting has become increasingly popular in recent years due to its energy efficiency and long lifespan compared to traditional incandescent and fluorescent lighting. However, some people have raised concerns that LED lighting may cause discoloration or fading of objects, fabrics, and surfaces over time. In this article, we’ll examine the evidence on whether LED lights can cause discoloration.
How LED Lights Work
LED stands for “light emitting diode”. LEDs produce light through electroluminescence, which occurs when electricity passes through a semiconductor material. This effect allows LEDs to emit light in a very narrow spectrum compared to other light sources like incandescent bulbs, which emit light across a broad spectrum.
The light spectrum emitted by an LED depends on the chemical composition of the semiconductor material used. Most white LEDs are actually blue LEDs coated with a yellow phosphor layer, which combines to produce white light. Some key advantages of LED technology include:
- High energy efficiency – LEDs convert over 80% of energy into light
- Long lifespan – LEDs can last up to 100,000 hours
- Directional lighting – LEDs emit light in a specific direction
- Compact size – LEDs are very small in size
Do LED Lights Emit UV Light?
Ultraviolet (UV) radiation is one potential cause of discoloration. Some sources claim that LED lights emit high levels of UV light in the UV-A spectrum (315-400 nm wavelengths). However, most research indicates that standard white LEDs emit very little UV radiation, especially compared to sunlight.
One 2017 study tested several different LED bulb types and found that most emitted extremely low UV-A radiation, similar to incandescent bulbs. Only a few specialty “UV” LEDs designed to emit UV light for disinfection purposes emitted appreciable UV-A. The researchers concluded:
“Well-designed LED lamps do not emit any significant level of UV radiation and are suitable for use even in museums exhibiting highly UV-sensitive objects.”
Another analysis by the International Commission on Illumination (CIE) also found negligible UV emissions from standard white LEDs. Therefore, most evidence suggests UV light is not a major cause of LED-related discoloration.
Do LED Lights Produce High Intensity or Heat?
Some claim that the high intensity and heat output from LEDs contribute to discoloration of items. However, LEDs actually produce very little heat compared to other lighting:
| Light Source | Heat Output |
|---|---|
| Incandescent bulb | 90% heat |
| Fluorescent tube | 75% heat |
| LED | 10% heat |
This is because LEDs are designed to focus energy into light rather than heat. Higher temperature can accelerate degradation of vulnerable objects. But thanks to their efficiency, LEDs run significantly cooler than other options.
LED intensity is also modifiable using dimmers, so light levels can be adjusted as needed. Overall, there is little evidence that LEDs damage items due to excessive heat or intensity alone.
Do LED Lights Emit High Blue Light?
The blue light emitted by LEDs has raised more concerns about discoloration. Some studies have observed damage to fabrics, artwork, and other materials when exposed to high levels of blue light over time.
Blue light is higher energy and thus more damaging than lower wavelength light. Standard white LEDs emit a high proportion of blue light to produce a cool, white output. This peaks at around 450-470 nm wavelengths.
For comparison, here are the blue light emission levels of some common light sources:
| Light Source | Blue Light Emission |
|---|---|
| Sunlight | High |
| Fluorescent | Moderate |
| LED | High |
| Incandescent | Low |
High blue light emission is inherent to the LED design. But steps can be taken to mitigate potential damage from LED blue light, discussed next.
Strategies to Reduce LED Discoloration Risk
If you’re concerned about LEDs causing fades or color shifts, here are some tips to minimize the risks:
- Use LEDs with lower color temperature – Warm white LEDs below 3000K emit less blue light than cool white above 4000K.
- Use LEDs with diffusers – Diffusers spread light and reduce intensity on surfaces.
- Install UV filters on LEDs – Adding a UV-A filter can reduce most remaining UV emissions.
- Use dimmers to lower light intensity as needed.
- Limit light exposure time with timers or motion sensors.
- Position lights further away from vulnerable objects.
With proper selection and positioning of LED lighting, the risks of discoloration can be greatly reduced for most applications.
Specialty LEDs Reduce Discoloration Risk
Several manufacturers now produce LEDs specifically designed to minimize damage to sensitive objects. These use alternative phosphor formulations to reduce blue light emissions. Here are some examples:
| LED Type | Features |
|---|---|
| Amber or Warm White LEDs | Low blue light, low UV emissions |
| Violet-Pumped Phosphor LEDs | Low blue peak, broad spectrum |
| RGBA LEDs | Tunable spectrum, adjustable blue |
These specialty LEDs are designed with conservation lighting applications in mind. Major museums like the Smithsonian use amber and violet-pumped LEDs to safely light sensitive artifacts and documents.
Conclusions
To summarize key points:
- Most standard white LEDs emit very little UV radiation, minimizing this discoloration risk.
- LEDs generate much less heat than other lighting, reducing damage from temperature.
- The blue light component of white LEDs has the highest discoloration potential.
- Special LEDs are available to minimize blue light for preservation use.
- With proper LED selection and positioning, discoloration risks can be mitigated.
In most cases, LED lights do not cause significant discoloration or fading when used properly. The advantages of LED efficiency and longevity generally outweigh a small risk of material degradation over very long exposure times. However, extra care should be taken when lighting sensitive or vulnerable objects.