LED Color Temperature Explained

LED Color Temperature Explained

Polar Ray Admin

Light, as humans perceive it, is a form of electromagnetic energy that falls on a small part of the spectrum that is visible to the naked eye. That light ranges in color from longer wavelengths at the red end to shorter wavelengths as it approaches the blue-violet end of the visible spectrum. Invisible light waves of longer length than red include infrared radiation, microwaves and radio waves, respectively. Shorter light waves run from ultraviolet through X rays and into Gamma rays.


Visible light also has two other interesting properties; it can behave as both a wave and a particle, and its color can be expressed as a temperature.

“Wait,” you say, “do you mean red light feels different from blue?” The answer is “no,” at least in the tactile sense. But psychologically and functionally, the answer can be a very definite “yes.” That’s where an understanding of what “color temperature” refers to becomes important in your choice of lighting.

The concept of color temperature dates back over 100 years when British physicist William Kelvin observed that as he heated a block of carbon, its color changed predictably with its temperature. As it reached 1350° F (~725° C) the carbon began to glow red. As the temperature rose, its color began shifting through orange and yellow to green and, at around 8,500° F, it began shifting to blue. Kelvin also pioneered research into temperature measurement and a new scale was developed starting at absolute zero (-273° C) and named for him. Thus, color temperature is measured in “degrees Kelvin” (°K) with 1,000°K being very red, 3,000°K white with a touch of yellow, and 7,000°K being sky-blue.

Of course psychologically, we refer to red, orange and yellow as “warm” colors and greens and blues as “cool,” which is just the opposite of their color temperatures expressed in degrees Kelvin.  Other popular marketing terms help to confuse matters like “soft white”.  “Soft white” is typically used interchangeable with “warm white” in the light bulb world.  To be safe it is always

best to avoid the marketing terms and seek out the actual Kelvin color temperature which is always printed somewhere on the light bulb or packaging.

LED Lighting and Color Temperature

LED lighting offers many benefits and features that were difficult, if not impossible, to achieve with other lighting technologies. Many of the obvious benefits, such as much lower energy use, substantially longer life, and lower overall heat generation are generally well known. Another feature that allows for dramatic appearance and productivity benefits now and in the future, involves the color temperature of the light produced by LEDs.

LED lighting technology allows for very pure colors to be generated. Fluorescent light bulbs and Compact Fluorescent Lights (CFLs) often emit light with spectral deficiencies that render colors inaccurately producing ghostly green skin tones and washed out colors.  Since the crystals in LEDs glow at very specific wavelengths and color temperatures, higher quality LED bulbs can be made to cast light in precise colors and intensities that can be matched to specific residential and commercial lighting applications.

Choosing the right color temperature in lighting can have dramatic effects by creating moods and environments conducive to the purpose of the space. Cooler (higher Kelvin degree) light enhances most tasks like reading, office work or manufacturing while warmer (lower Kevin degree) light tends to evoke calmness and intimacy so it is commonly preferred in homes, high end restaurants and boutique retail stores.   

Matching the color temperature of lighting to a space’s function is an important design choice, both for residential and commercial applications. The chart below gives examples of color temperatures best suited for typical living and working conditions.

The most common warm white LED color choices are:


Looks just like the light emitted by a common incandescent bulb


White light with a touch of yellow to add some warmth (a popular halogen color)


Neutral white light (no yellows or blues)


A very cool neutral white


A very cold white that some call daylight, others call moonlight

Polar Ray LED Lighting Solutions has been a leading supplier of LED lighting technology for both commercial and residential use for over 30 years. We offer insights, experience and support for LED lighting applications that is rare in a marketplace crowded with businesses that are newcomers to this highly sophisticated technology.

We invite you to learn about our company and see the many products we offer on our website, Polar-Ray.com, and to visit us often for a look at the newest LED lighting products. When you're ready to make a purchase, we'll be here to answer any questions you may have and help guide you to the best LED lighting products for your home, office or business.

We’re also available for personal help with product information and placing orders Monday through Thursday, 9am to 5pm and Friday, 9am to 4pm MST at 1-888-494-5773 or by email 24/7 at info@polar-ray.com.