Getting in Tune with LEDs

Getting in Tune with LEDs

Key Points

  • Color-tunable LEDs can deliver light in color temperatures ranging from warm to cool.
  • Correlated color temperature (CCT) measures the color temperature of the light emitted from a bulb.
  • Three types of color-tunable products are available: dim-to-warm, white-tuning and full-color tuning.

LEDs are well known for their efficiency, long-life, durability and other benefits—but the latest generation of products are color tunable as well. Individual LEDs with different colors have been around since the early days of solid-state lighting, but recent technology advances in colors, controls and capabilities have expanded their range of potential applications—making them a hot topic in commercial indoor lighting.

Tuning lights for tone or color

To fully grasp how color tuning works, it’s important to first understand color temperature. Light has different tones or colors, ranging from cool (bluish) to warm (yellowish) tones. Different tones produce different effects. For example, a warm tone can create a relaxed atmosphere in a restaurant, while a cool tone can be used to promote concentration in an office or classroom.

Correlated color temperature (CCT) measures the color tone of the light emitted from the bulb in degrees Kelvin (K). It doesn’t measure the heat of the bulb, only its color. The higher the CCT, the cooler the light appears. Bulbs with a CCT below 3,200 K are considered warm, while those above 4,000 K have a cool appearance.

Types of color-tunable products

Color-tunable LED lamps are still fairly new to the commercial light market. There are three types available:

Dim-to-warm products mimic the dimming performance of incandescent or halogen lamps, becoming warmer in appearance as the product dims. The light color temperature is 2,700 to 3,000 K at full output, and can be reduced to as low as 1,800 K (the color of candlelight) as the product is dimmed. The light color temperature changing and dimming qualities would be very useful in restaurants, hotel lobbies, guest rooms, theaters and museums.

White-tunable fixtures have two or more sets of controllable LEDs: one with a warm-white color temperature (around 2700 K) and the second with a cool-white color temperature (5,000 to 6,500 K). Raising and lowering the output of the LEDs can create white colors between the two color points. White tuning allows you to change the color temperature of light from warm to neutral to cool in appearance. Such color tuning can be used to:

  • Simulate daylight or candlelight to set a mood.
  • Match room finishes to seasonal variations, remodeling or brand/theme changes.
  • Suit the needs or preferences of a new tenant.
  • Control behavior—warm light for a calming environment, cool light to focus attention.

Full-color tuning products have three or more different-colored LEDs that can be varied in output. The main advantage of full-color tuning is the ability to move beyond different temperatures of white light to a mixture with a distinctive color pattern. You can create a white, office-like appearance and then switch to a purple theme. This can be very useful in applications such as restaurants and theaters. The control of individual LEDs gives you the option to mix the spectrum to enhance colors in retail or museum displays.

A bright future

Color-tunable LEDs are still emerging in the lighting market and they are not currently competitive with standard fixed-color products if efficiency is the main criteria. In most cases, color-tunable lamps have a lower efficacy—light output compared to power input—than fixed lighting systems, according to the U.S. Department of Energy.

However, color-tunable fixtures offer non-energy benefits—such as creating atmosphere or mimicking daylight—that provide a more visually dynamic indoor environment. Some models include built-in wireless communication that allows for individual, remote control. In applications where occupant satisfaction, patient well-being or vivid displays are important, color-tunable LEDs offer capabilities not practically available with other lighting technologies.