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What is color temperature?

Posted: 2013/07/04

Color temperature is a measure that tells us the color light emitted from a light source. Typical color temperatures range from 2,700 K to 9,000 K. Lower color temperature light emit what we normally call warm or yellow light, while moderate to higher color temperatures emit neutral or cool white light.

The spectrum of colors along the color temperature scale, ranging from 1000 K to 10,000 K.

Warm white light (typically around 3000 K) is typically appropriate for residences and other venues where a relatively calm, warmer ambiance is preferred. We are typically accustomed to the 3000K color temperature of incandescents, so oftentimes replacement bulbs are rated at 3000K as well. Cool white light (typically around 7000 K and higher) is usually preferred in active or professional settings such as in offices.

Why is it called color temperature?

The actual temperature of the LED light is not related to the color temperature of the light. It is actually related to what is called a black-body radiator. Put simply, a black-body radiator is any object that emits light when it is heated, such as an iron bar, or the tungsten filament in an incandescent light bulb. The color temperature is the corresponding color that is emitted by these black body radiators when they are heated to each temperature.

What needs to be considered?

The first and foremost consideration to keep in mind is the intended application of the LED lights. If the lights are to be installed in a residence where a warmer, cozy ambiance is preferred, warm, low color temperature lighting is idea. For schools or offices, neutral or cool light is better suited.

A comparison of how the same room would look under low color temperature (left) and high color temperature (right) lighting.

People are often averse to switching to LED lighting because they falsely believe that all CFLs and fluorescents emit a cold, high color temperature light, and that LED lighting is similar in this respect. This is a misconception - before CFLs became more commonplace, most consumers only purchased incandescents, which tend to all be of lower color temperatures (warm white color). With the advent of with CFLs and LEDs, however, both low and high color temperature lights became available. Uninformed consumers unintentionally purchased high color temperature products for their bedroom when a softer, warm white color should have been selected instead. It is important that consumers are made aware that both CFLs and LEDs can be freely adjusted to whatever desired color temperature, they simply need to be conscious of this aspect when selecting lighting products.

In order to create a warmer, lower color temperature light, red LED phosphors must be added to the phosphor mix. Because human eyes are most sensitive to green light, taking some of the green light to create more red light slightly decreases the total lumens output of the LED light. Also, in some cases, warm white LED light can be more expensive because red LED phosphors have a higher cost than yellow or green phosphors.

Color temperature is an aspect of lighting that addresses our emotional, human response to light. As such, it is very important for the final lighting installation but not always easy to identify the precise color temperature needed. Furthermore, if lower quality products are used, color consistency becomes unpredictable, especially over time. We at Beijing Yuji specialize in LED phosphor and packaging, allowing us to produce a wide variety of high-quality products that perfectly suit our customers' needs. Contact us for more information!

Author: Alex

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