Quote:
When the first automotive HID headlamp was demonstrated by a major
European lighting manufacturer to automakers, in the early mid 1990s, it
was a very well-designed optic, given the infant state of the art at the
time. It handily outperformed most halogen lamps, and of course consumed
less power. It was based on modified HPS (high-pressure Sodium) arc
chemistry, and had a very similar operating appearance when warmed up to a
halogen headlamp.
The automakers reacted favourably to the increased performance and reduced
power consumption, but rejected the lamp on the grounds that customers
would be unwilling to pay any premium for a lamp that looked the same as
the ordinary kind, regardless of increased performance.
Now, back to that very large "white" boundary: it was a very simple matter
to rework the arc chemistry in the auto HID lamp to create high spikes in
the blue and blue-violet. This created a markedly new/different
appearance, which the automakers' marketing boffins pounced on. Here was
something they could sell on appearance, something non-owners would notice
and come in to the dealers to ask about. No visual benefit to the blue
spikes, and the resultant colorimetry still fit within the legal "white"
boundary: Voila.
I still think this is baloney--unless the blue "spikes" are what raised the overall color to 4500K.