Correlated Colour Temperature: Globe Types and Lens Colour
Correlated Colour Temperature
A lot of people think that the colour temperature relates to the brightness of light output – this is entirely false. The colour temperature
relates solely to the colour of the light and nothing else. A light with higher kelvin can have less light output than one with lower
Kelvin. The reason for this is that we use Correlated Colour Temperature (CCT) to describe colour of light, rather than the true kelvin
scale that relates to light output based on heat.
Here is a simple list of light sources and their approximate CCTs in kelvins to give you a better idea:
- 1700 K: match flame
- 1850 K: candle flame
- 2700-3300 K: incandescent light globe
- 3500 K: 100W quartz halogen light globe
- 4100 K: moonlight
- 5000 K: horizon daylight
- 5500-6000 K: daylight
- 6500 K: overcast daylight
The short of it is, the lower the Kelvin, the light appears more yellow, the higher the Kelvin, the light appears more blue.
At 6000 Kelvin (close to daylight), the light appears cool white with a slight blue halo.
3500K QH vs 6000K HID
Quartz halogen bulbs at 100 Watts are rated at 3500K, which is in the yellow end of the colour temperature spectrum. HID systems
typically come in either 4200K or 6000K. 4200K is whiter than a QH globe, but still sits just inside the yellow spectrum. 6000K is
considered to be cool white and close to daylight.
Globe Types and Lens Colour
Now that you’ve got a concept of colour temperature and the kelvin rating of the two globe types in Xray Vision driving lights, we can show you how to increase the kelvin output of the light by using blue filter lenses.
Blue lenses on QH driving lights take the Kelvin from 3500K up to 4000K, and on HID driving lights with 4200K globes from 4200K up to about 4700K.
QH (Quartz Halogen)
The blue lens on Xray Vision driving lights takes some of the yellow spectrum out of the light being emitted, giving the user a cleaner, whiter light on the road. There is a very slight loss in light output (about 5%), so people wanting the maximum light output will still prefer the clear, but most will see the benefit as shown in the two photographs.
The other advantage is higher Kelvin gives greater clarity in poor visibility situations such as mist, rain or fog.
HID (High Intensity Discharge)
Blue lenses on HID globes aren’t necessarily required as the light is already considerably whiter, however some people prefer their
lights to shine much closer to daylight in colour making them whiter and crisper using the blue lens. Some people also just like the
physical appearance of the blue lenses when they’re fitted to their vehicle, and that’s okay too!
Blue or clear lenses are available right across the range of Xray Vision driving lights (all models and beam patterns) for no extra
cost – representing great value.