Xenon Bulb

[chas3]

I ordered a pair of two xenon bulbs, Philips D2S 85122+. They were ordered on ebay and the seller posted them as new, never used. However, I am not sure they actually are brand new, the glass ball in the middle of the bulb is half yellow colored. Could somebody confirm if brand new bulbs should be like that?

The camera didn't exactly pick up the yellow tint I am talking about:





There is a grainy yellow tint on the side of the electrode. Only the small glass ball at the middle of the bulb has it.

I edited one of the photos to highlight the yellow tint area, since the camera didn't quite catch it.

[kkodal78]

that seems right. all the ones i bought had the yellow stuff in it as well

[chas3]

Cool, thanks.

PS: the headlight HID cover was a PITA to remove without taking off the bumper

[X5Sport]

It should be a Metal Halide salt which evaporates as the lamp fires up. It's the make-up of the metal halide salt that determines the colour temperature of all HID lamps. Once the bulb cools down the metal halide salt condenses out again and you can then see it - at least that's my theory. The science fits.

It might also just possibly be a filter coating material to control the UV output from the bulb. As these are Arc lights they give out high UV at levels which can induce 'arc eye' - ask a welder about that affliction as I'm told it's like having sand thrown in your eye - so there may be a yellow filter to reduce the UV levels.