Many people think that the higher “K” number (e.g. 3,000K; 5,000K; 8,000K; 12,000K, etc…) the brighter their HID headlights are going to be… and they’d be wrong! This is because the K number doesn’t describe brightness, only color.
From left-to-right: 5,000K – 6,000K – 8,000K – 10,000K – 12,000K
When it comes to brightness, you get the most usable, real-world brightness (measured in Lux) in colors that more closely resemble the color of light created by the sun! Did you know that if you could see the sun in space it would look white? The actual color of the sun is 5,800K not that yellow color that you were taught to color with crayons as a child. The more you deviate away from the 5,000K – 6,000K colors, the harder the time you have “perceiving” the intensity of the light! At the end of the day, it’s all about human evolution and perception – we can’t see ultraviolet light very well, so 8,000-12,000K colors aren’t very bright to us and we can’t see infrared colors very well, so 3,000K golden yellow is also less bright!
In the test in the video above, each color produced different amounts of brightness and usable light. Because of this, you’ll see that the 5,000K color HID was the brightest of all 7 tested, powered by both a 35w or a 55w ballast:
3,000K with 35w ballast: 350 Maximum Lux
3,000K with 55w ballast: 490 Maximum Lux
4,300K with 35w ballast: 1,070 Maximum Lux
4,300K with 55w ballast: 1,510 Maximum Lux
5,000K with 35w ballast: 1,140 Maximum Lux
5,000K with 55w ballast: 1,430 Maximum Lux
6,000K with 35w ballast: 980 Maximum Lux
6,000K with 55w ballast: 1,350 Maximum Lux
8,000K with 35w ballast: 970 Maximum Lux
8,000K with 55w ballast: 1,340 Maximum Lux
10,000K with 35w ballast: 750 Maximum Lux
10,000K with 55w ballast: 890 Maximum Lux
12,000K with 35w ballast: 420 Maximum Lux
12,000K with 55w ballast: 570 Maximum Lux
If you’re looking for information on LED headlight bulb color and brightness, you’ll find that the same information exists but in fewer color options. Color and brightness in headlights has the same relationship regardless of if you’re looking at HID or LED.
Disclaimer:
Street legal in the USA for Fog Light use. Not compliant with DOT / FMVSS108 and not street legal in the USA for Headlights. Certain specialty vehicles strictly limited to off-street use and not having DOT registration or license plates may use these products exclusively off-streets. International street legality varies by country. This usage regulation is not unique to a specific bulb, ALL LED and HID bulbs from all other brands, regardless of marketing claims, are prohibited from street use in halogen headlights in the USA.