Color Temperature

What Is Color Temperature?

Artificial lighting comes in a wide range of colors to suit many different applications. In order to quantify this, the color of lighting is measured on a color temperature scale using Kelvin (K). Formally known as the Coordinated Color Temperature (CCT), this scale ranges from 1,000K all the way up to 10,000k, with most commercially available lights falling in the middle of that range. The lower end of the scale range has a “warmer” feel with a more red or orange hue to the color. The higher end of the scale on the other hand has a “cooler” feel to it and has a more white or blue color hue. This range of color temperatures serve a wide number of applications, some requiring specific kelvin ratings and others being far more flexible and adaptable to a larger kelvin range.

Color Temperature Scale

As mentioned previously, color temperature is measured in Kelvins, ranging from 1,000K to 10,000k. Natural sunlight varies from approximately 5,000k to 6500K, depending on the time of the day and weather conditions. The overwhelming majority of commercial and industrial lighting falls into this range, due to its versatility and close approximation to sunlight. The below graphic describes the overall kelvin range and equivalent types of lights that fall within this scale.

How Kelvin is Measured

Those knowledgeable in scientific fields may already be familiar with the use of the Kelvin Scale (K), which is often used in conjunction with celsius and Fahrenheit for temperature measurement. In the lighting world, this very same scale is used to express the visible color hue of the light produced, which is referred to as color temperature. This color temperature is determined by finding the approximate theoretical temperature in Kelvins that a black-body radiator must be heated to in order to create a visible color.

For example, if a piece of steel were heated until it glows from a red or orange hue, to a yellow and then a white or blue hue, this would cover most of the color temperature range visible to the naked eye. These colors would be coordinated with the equivalent temperature in Kelvin (Celsius + 273) that the steel was heated to in order to create them. This is the basis upon which all color temperature measurements are founded.

Color Temperature Applications

Different color temperatures are used depending on the application and the desired mood. As mentioned earlier, color temperatures closer to the lower end of the kelvin range give a warmer feel, which tends to be popular for residential and certain commercial and industrial applications. At the other end of the spectrum, higher color temperatures produce a white or blue light which most closely resembles natural sunlight. Below is a listing of applications for the most common color temperature ranges.

Warm White
This is a common color originally created by many older incandescent lamps, as well as other light sources such as candlelight. Ranging from 2,700K all the way up to 3,300K, this light is at the bottom end of the commercially available LED color spectrum, producing a red or orange hue. Out of the entire color spectrum, this is by far the most comforting and relaxing for individuals.

Today, it is available in certain artificial light sources such as LED lighting, and is commonly used for residential and retail spaces looking to set a cozy and inviting atmosphere for guests and customers. Typically, this light source will be used in things such as lamps, chandeliers, bathrooms and living rooms in homes and speciality product displays in retail settings.

Cool White
This middle range of color temperatures is a considerably whiter form of light, however it is just below the Kelvin temperature that blue light occurs. Cool white lighting falls into the 3300k to 5300k range, and is commonly seen in fluorescent tube style lighting used throughout office, warehouses and other commercial settings. With a less orange or red hue, this color does more to stimulate than relax in regards to its effect on individuals.

This is an exceptionally popular color temperature range in today’s commercial and industrial environments due to its stimulating effect on workers and boosting efficiency. It also is used in common use in residential applications for high traffic areas where increased awareness and visibility are important, such as entryways, porch lights and garages.

Daylight
At the high end of the Kelvin scale of commercially available lighting, this color temperature range has a blue hue to it, and ranges from 5,300k to 6,500k. Known as the daylight range due to its close approximation to the color temperature of actual sunlight, it excels at producing an intense colored light that commands attention and provides maximum stimulation.

Lights using this color temperature range are popular in all different types of environments, including residential, commercial and industrial applications. Since this color range most closely replicates natural sunlight, it is very popular for those who suffer from seasonal depression in areas that do not get much sunshine for extended periods of time. It is also popular in commercial and industrial environments due to it providing the best color rendering out of the entire Kelvin spectrum, improving visibility and subsequently safety.