HID bulb chart showing base types and color temperatures from 30…

HID Bulbs & Colors

4300K is the color temperature used by most vehicle manufacturers because it produces the most visible light with the least heat (highest efficiency).

With separate High & Low bulbs, the lows CAN be wired to stay on with the highs; with HID, the lows SHOULD be wired to stay on. A simple jumper across the dimmer switch (from input to low) will do that.
Low Beam - H7
Hi Beam - H1

See also:

Owner caption August 2012 · Photo 4702 of 5000