Why do HID headlights look blue when they are turned on?
The color of a light is determined by its color temperature. The interaction of the electrical arc and the gasses inside of the capsule give off a higher color temperature (4,100 K) that is closer to true white. So when you compare the color of a halogen headlights (3,200 K) against the color of HID headlights, the HID lamps look blue/white and the halogen lamps appear more yellow.
