a bluer shade of white

after my previous foray into the world of performance (looking) headlights, i've discovered the existence of halogen bulbs which are filled with xenon gas. this, of course, allows the marketers to legitimately use the word xenon in association with these products.

nevertheless, these should not be confused with the actual HID lamps which, while also filled with xenon gas, do not have a filament (a feature of halogen bulbs), use a different technology to produce light, and have different power requirements. however, the filling of a halogen bulb with xenon gas does result in a bluer light. there are also some halogen bulbs which are coated with a blue film to achieve a similar look. to quote an ebay guide on the topic:

Xenon gas-filled bulbs and other halogen 'xenon' bulbs are simply a standard halogen bulb that is either coated with a blue film on the outside and/or filled with a gas to imitate the look of a true xenon HID bulb. These bulbs produces much less light than xenon HID bulbs and often less than that of a standard halogen bulb. Xenon gas-filled bulbs also suffer from a short 6-month life-span.

i don't know that they necessarily produce less light than a standard halogen, though i suppose any coating would attenuate the light output. and i hope the short life span doesn't prove that accurate, but should i need to purchase any more bulbs, i'll know to look on ebay where where i can get a pair for about 1/3 what i paid for my current ones!

for more information on HID xenons, see also for example
http://www.alpha-bid.com/XenonBuyingGuide.html
http://www.wheelsmart.com.au/HID.aspx