Its like the engine break in period. Once the HID bulb is breaks in or burns a certain amount of hours the salts inside change and it becomes bluer. I didn't remember the techinical issue of it but you can read it over at www.hidforum.com . I'm a member there.


That is why all OE stick with 4100K cause over time it'll color shift. So even with color shift you'll have decent light output throughout the life of the HID. You put 6000K or 8000K and once the light burns in it'll get bluer and you'll have Smurf HID with even worse light output.