Difference Between 5000K and 6500K Bulbs

When searching for "daylight" or color-balanced LED lights, you may frequently come across two different color temperature options: 5000K and 6500K.

Confusingly, you might often hear one being recommended by one expert, only to have that recommendation contradicted by another expert. What gives?

In this article, we'll go over the differences between the two color points and what they mean for artists and studio lighting.

 

Difference Between 5000K and 6500K

First and foremost, the difference between 5000K and 6500K can be thought of as the relative amounts of "yellow" vs "blue." On a relative basis, 5000K is yellower than 6500K, and 6500K is bluer than 5000K.

Rendering the two color points on computer monitor produces the following results (below).

 

You likely will see that 5000K appears slightly yellow, and 6500K appears as pure white. This is because LCD screens are calibrated to show 6500K (or D65) as "true white" - and the device you are reading this article on is also likely to be calibrated to D65. (Note that your device may have a "night shift" feature that adjusts the monitor color depending on the time of day, altering the color appearance of the swatches below).

Below is the relative spectral power distribution of 5000K (black) and 6500K (blue). You will immediately notice that the 6500K graph shows a higher amount of blue, and lesser amount of yellow and red, when compared to 5000K.

 

Although the light color of natural daylight varies significantly depending on the time of day, season, weather and geography, 6500K is the commonly accepted color point that is considered the most representative color that matches natural daylight.

We may assume, quite naturally, that natural daylight is a true white color point. After all, art and paint instructors commonly advise students to use natural lighting ("the best kind of lighting") in their studios through a north-facing window.

But daylight (not sunlight) is actually quite blue - which, when you think about it, makes sense considering how blue the sky is. Even a cloudy, overcast day has significant amounts of blue sky in it, as the clouds are simply scattering the blue light that shines from above them.

From far away, even though LCD screens are calibrated to a "white" 6500K color point (D65), they can also often appear to emit a dull, blue-ish light.

 

Now that we got the theoretical out of the way - which one is best for you? Keep reading to see our practical recommendations.

 

Do you want to paint under daylight?

So the practical advice for artists is: if you're looking to replicate natural daylight, choose a 6500K bulb. Be aware that the bulb's light color, just like natural daylight, will appear slightly blue.

Choosing a 6500K bulb might be especially important if you want to use a mix of natural and artificial daylight. If, for example, you work on a painting near a north-facing window during the day, but want to continue working on the same painting under similar lighting conditions at night, you will want to select a 6500K bulb.

Notice how in the photo below, the light color from the ceiling skylights are cooler than the 5000K high-bay lights. For a color-sensitive environment, this color temperature mismatch may result in inconsistent lighting conditions between daytime and night time.

 

Do you want to paint under neutral light?

On the other hand, 5000K differs from natural daylight, but can provide many benefits over 6500K.

First of all, oftentimes artwork is ultimately displayed or showcased in an indoor installation where the color temperature is much warmer - typically 2700K in a residential setting, and 3000K-4000K for a commercial or gallery setting. In this context, 5000K is much closer than 6500K, which can make 5000K a better choice for better "seeing" what the ultimate audience may see.

Second, 5000K can provide a softer and more relaxing light than 6500K. Because of its reduced blue content, 5000K may appear more pleasant and balanced. Indeed, 5000K has a very balanced spectrum as well, with approximately equal amounts of each wavelength present.

The nice feature of 5000K light is that it offers a reasonable compromise between color acuity that is lost at lower color temperatures, and blue-bias present in 6500K and natural daylight. For art studios that don't utilize much natural daylight, 5000K can work perfectly as the primary light source.

Many users in graphic arts, printing and textile industries will use a D50 (5000K) light source to perform color critical tasks.

 

There is no "wrong" color temperature choice, but be aware of CRI

Have you ever wondered why you don't consciously think of natural daylight as being blue? Or even under the constant changing color temperature of the sky across the day, seasons and weather, we're don't constantly notice a difference?

The human vision system is quite adept at "chromatic adaptation" - a mechanism that allows our eyes to dynamically normalize a white point depending on ambient lighting conditions.

Thanks to this adaptation, despite its variability, natural daylight is indeed an excellent light source for performing visual tasks.

And when natural daylight is insufficient, as long as a light source has an excellent CRI, color temperatures between 4000K and 6500K are actually all reasonable color points for accurate color judgement, and our eyes are remarkably skilled at adapting to each of these lighting conditions.

 

Where to Purchase 5000K and 6500K LED Lamps

Waveform Lighting offers 95 CRI 5000K and 6500K T8 LED tube lights that are both direct-wire and ballast compatible. See here for more details.