d2s or d1s hid bulbs

is the color temp printed on the bulb
or do you have to look it up some how ?

I don't think its listed on the bulb. If you are looking this up for HID conversions for cars, I believe they just tint the glass.

the bulbs mist have part numbers or some thing

I am amazed no one has an answer

markdi:

http://faq.auto.light.tripod.com/hl-hid-bulbs.htm

that should give you a bulb # vs tint cross section, scroll down.

what I am really after is
if some one sells me a 4300k bulb how will I know for sure
they must be marked or have part numbers

also can a person tell a new bulb from an old one ?

well philips and osram are the only US suppliers of DxS lamps, and both are rated 4100K with color shift to 4350 after 500 hours (more so philips than osram). neither makes 4300 lamps, they just shift to that temp after couple hundred hours. the other option is for philips, if there is a + sign after the 5 digit part # (85xxx+) then it is 5000K, meant to be used for warranty replacement to match up with a used OEM lamp so both have similar color characteristics.

none of the OEM makers tint their lamps to get specific color, it's all in the optics/reflector and focussing how they can get a certain "color". there are aftermarket manufacturers from asia that might have other specific traits, but aren't made well with short lives.

hope that helped.

so the 5 digit number is the color temp

in a nutshell, yes. but no direct relation, so 85407 doesnt mean 5400K temp (it is 4100K to start and shifting up w/ age). 85xxx+ are easy, only Philips makes them, and a + means 5000K.

well I know that they change with time

are you sure that a 54ook unit would start at 4100k

anything made by philips or osram (with the noted exception of the "+" series) start out 4100K, shift to 4350 in few hundred hours. the other asian makers, i dunno about.