Colour temperature in HID lamps

I note there is a big difference in the colour temp of HID lamps - and it seems there is a preference in the lower temps - around 4-5000. I have only ever seen HID lamps in upmarket cars - where they seem to have a blueish tint - I have never even driven such a vehicle at night to compare with conventional head lamps - so I am reliant totally on the opinion of others in this. Is this just a matter of simple taste - or are there real benefits to a lower temp lamp - and if so why are many lamps still a higher colour temp.

Hi,

Yes, lower temp lamps produce more light per watt & are better for seeing at night basically.

anything over 6000K is considered pointless. I too shack my head when I see cars with the real blue tint lamps. More an annoying novelty, rather then real light imo.

And flashlights with 6000k+ are too just pointless. It really is best at 4000-4300. (thats my view) t varies with ppl's taste, but i srsly doubt 6000K+ is favoured.

As I posted in another thread:

Any bulb color temp above 4300 ish' causes a loss of lumens - all other conditions remaining identical - same bulb, ballast & power source. Also, higher color temps change our perception of the natural color of objects.

For overall output for flashlights where I'm looking for every Lumen possible, I prefer 4300K. My favorite color of all is 5000K. That's what I bought for my vehicle HID's. It's like a "Diamond White". There is very little Lumen loss with this color, but technically, some.

I find the 4250K of automotive D2S to be too blue.

4250K color is 4250K regardless of the lamp type. Normally a bulb in that range would never be considered blue-ish. My guess is that the D2S / D2S's that you've seen were not really 4250K or perhaps they were not broken in yet.

The "blue" range of light isn't really perceived until close to 5000K and it easily seen at 5500K and above.

.



Nice Pic showing different HID color temps



I have the temps marked somewhere but I can't seem to get to my files




3K, 3K, 4K, 4K
5K, 5K, 6K, 6K
8K, 8K, 10K, 10K
12K, 12K, 3K, 3K











.

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There's definitely no blue in 4300K lamps once warmed up. There is a little 5000K'ish in the first few seconds but that's it.

Patriot36 said:

4250K color is 4250K regardless of the lamp type. Normally a bulb in that range would never be considered blue-ish. My guess is that the D2S / D2S's that you've seen were not really 4250K or perhaps they were not broken in yet.

The "blue" range of light isn't really perceived until close to 5000K and it easily seen at 5500K and above.

Click to expand...

No, they are toyota OEM. (with about 500 hours)
It is that large blue spike in the SPD that does it for me.

MichaelW said:

No, they are toyota OEM. (with about 500 hours)
It is that large blue spike in the SPD that does it for me.

Click to expand...

In that case I just don't think they're spec'd properly. HID bulbs really don't get any warmer than 4100-4300K and as you can see from Lips' photo example that top row definitely doesn't have any trace of blue, nor do any of my 4200K - 4300K HIDs. As BVH indicated, traces of blue just barely start around 5000K. If I use my imagination, I can see some blue in the 7th box from the uper left but not hint of blue before that.

What do you think Bob?

A few things worth pointing out:

Only 4200k and below CCT lamps are allowed on the road legally. I'm not sure if this is explicit, or simply a de-facto law because none of the legitimate OEMs choose to release any >4300k lamps.

HID headlights appear more bluish to other drivers because of chromatic aberration in the projector housings. The short blue wavelengths are refracted more than the other colors, and tend to diverge from the headlight rather than striking the road. This blue "fringe" is what the other drivers actaully see most of the time. IMO it's more helpful to look at the actually road surface or objects lit up by the HID than the light itself.
Nexdt time you're walking by a road or parking lot you can generally have an easier time telling.

It is those spikes under 500nm that bug me
(page 9,10)
http://www.lrc.rpi.edu/programs/transportation/pdf/NITSA/holtNHTSAworkshop.pdf

I agree that there is way too much blue on initial startup, but that does away within 15 seconds or so.


Maybe I am melatonin deficient
http://www.lightcongress.com/presentations/2007-Joan-E-Roberts.pdf

2xTrinity said:

A few things worth pointing out:

Only 4200k and below CCT lamps are allowed on the road legally. I'm not sure if this is explicit, or simply a de-facto law because none of the legitimate OEMs choose to release any >4300k lamps.

Click to expand...

This is no longer true, BMW does in some cases offer 5000K (4900K) Philips model 85123 or a new model (for the aftermarket) which is DOT compliant 85122CV (Crystal Vision). They used to offer 85122CM (color match) to match the color of a used bulb as they color shift upward with age. As the std 4200K age past 100 hours they gradually color shift upwards toward 4900K.

The new plus (85122+) version Philips are more color shift stable and longer term consistant lumens maintenance. These features are also available for D1S.

I believe Osram has a 5400K DOT compliant bulb. If true, this is the highest K value DOT compliant.

All euro cars with HID's ive see in my area, appear from my sight to be at least 8000K, really horrible colour. And theres lotsa lumen loss coz it's glare looks less then halogen, or that could be that their angled properly on the road.

Those "upmarket" cars flash blue with 4200k bulbs because of the mentioned fringe color shift on the very edges of the beam from the projector lenses they use. If you look straight at them they aren't blue. They don't shine blue light. They only look blue for an instant as you drive past because of the angle.

Many people on the auto HID forums seem for some reason to value this blue corona highly and will even rate/rank HID bulb housings based on their ability to produce this artifact. They even have contempt for well designed D2R reflector housings because those cannot produce this fringe effect at all to annoy other drivers :shrug:

XeRay said:

As the std 4200K age past 100 hours they gradually color shift upwards toward 4900K.

Click to expand...

Only 100 hours? Then the decision by VW to operate low beam HID DRLs seems really stupid.

These were new oem lexus bulbs in an '07 model. Maybe I am off in my calculation of hours (Chicagoland has a pretty good winter stretch, an hour runtime going to work, same for going home)

http://deepblue.lib.umich.edu/bitstream/2027.42/55201/4/98464.pdf

page 18, shows the comparison of ECE to SAE white space

It looks like HID start off at about 4000K CCT (aggregate)

I just found this


Norm

Very nice presentation, but why do the two pairs of 3K's appear not to match?

Brightnorm

Lips said:

.
Nice Pic showing different HID color temps
I have the temps marked somewhere but I can't seem to get to my files

3K, 3K, 4K, 4K
5K, 5K, 6K, 6K
8K, 8K, 10K, 10K
12K, 12K, 3K, 3K

Click to expand...

Lips, are those actual color temperatures advertised temperatures? I didn't think that 3000K color was possible in HID and likewise for 12,000K. Am I mistaken to have understood it that way?

2500K HID is filtered.
and the extreme blue is also filtered.