HID stands for "high intensity discharge" as
the light is produced by an electric arc, not
a glowing filament.
The blue/purple light you see when looking at
them is interference/noise light from the arc
and is not the actual main color of the light
they produce. It's stray light. I'm noticing
that newer HID models don't seem to produce
quite as much of this light (compared to say
the OEM HID on Porsche 993s which have a very
pronounced sharp brilliant blue aura).
T.
