More power! ... for my lights

[Perky]

Stealer of Souls wrote this about Hella Cool Blue bulbs:

They honestly look brighter. But this'll be due to the colour of the light and how it reflects off the road/signs. I suspect that the lower colour temps of the standard halogens and xenons lead to lower amounts of light reflected back from the surface they strike. This gives the cool blue the impression of more light.

I am intrigued by your experience, but this cannot be the reason. Remember that the blue filter is not adding anything to the light output. Any blue light coming out of the Cool Blues is also present in the unfiltered light of standard or better bulbs. Standard bulbs will not cause less light to be reflected from surfaces; they will cause more light to be reflected.

As I see it there are two possibilities for the subjective impression that the blue bulbs are brighter. Either there is something about blue light that makes it seem brighter to our eyes or there is something about our eyes' response to blue light (or the absence of other colours) that makes them more sensitive overall. In the former case, we would have the impression of increased brightness but would actually be able to see less. In the latter case, it is possible that we could see more, but our increased sensitivity would still be counteracted by the fact that there was less light.

My limited understanding of the issue suggests that for a couple of reasons (concerning the physics of light and the mechanics of vision) bluer light is subjectively associated with glare -- remember those gimmicky Blu-blocker and Eagle-eye sunglasses. So in fact the former is the case: the blue light seems brighter but because there is less light we actually see less.

The Narva's have a much thicker blue coat on them, which I suspect is the reason I found them to be under performers.

This doesn't surprise me -- there is a bit of BS on the Narva website. They claim the Blue bulbs are 'brighter' than standard but show only higher colour temperature, not higher output. In fact they are dimmer. (It is possible for blue bulbs to be brighter than standard, if they have xenon in them, but they will always be dimmer than the same bulb without the blue filter.)

Philips-Osram are somehow related to Hella... But I don't know the actual link, but I think that Hella bulbs are made by Philips (??).

Yes. My recollection is also that the Hella Xenon bulbs I've seen are made by Philips. But the specificities of OE manufacture are twisted and mysterious. I did some checking on the web and as far as I can tell Hella, Philips and Osram are separate, rival companies. Narva is owned by Philips. Nonetheless, I think my Narva bulbs are made by Osram.

[Stealer Of Souls]

Yes. My recollection is also that the Hella Xenon bulbs I've seen are made by Philips. But the specificities of OE manufacture are twisted and mysterious. I did some checking on the web and as far as I can tell Hella, Philips and Osram are separate, rival companies. Narva is owned by Philips. Nonetheless, I think my Narva bulbs are made by Osram.

And the mystery continues. Where's Ccooby Doo when you need him...
I think there's a strong link between Hella and Philips. They both market near identical bulbs. Heck the adverts are even REALLY similar.

I am intrigued by your experience, but this cannot be the reason. Remember that the blue filter is not adding anything to the light output. Any blue light coming out of the Cool Blues is also present in the unfiltered light of standard or better bulbs. Standard bulbs will not cause less light to be reflected from surfaces; they will cause more light to be reflected.

As I see it there are two possibilities for the subjective impression that the blue bulbs are brighter. Either there is something about blue light that makes it seem brighter to our eyes or there is something about our eyes' response to blue light (or the absence of other colours) that makes them more sensitive overall. In the former case, we would have the impression of increased brightness but would actually be able to see less. In the latter case, it is possible that we could see more, but our increased sensitivity would still be counteracted by the fact that there was less light.

My limited understanding of the issue suggests that for a couple of reasons (concerning the physics of light and the mechanics of vision) bluer light is subjectively associated with glare -- remember those gimmicky Blu-blocker and Eagle-eye sunglasses. So in fact the former is the case: the blue light seems brighter but because there is less light we actually see less.

I can't explain it fully. But I swear to you that when you look out the windscreen, the cool blues show up more on the road. The most undeniable fact is that they reflect of street signs lots better. When on a dark stretch of road (like the motorway heading North past Albany) the headlights will easily illuminate the reflective centre markers for as far as the eye can see when on high beam. And when on low the reflections are better.

What I'll do. I have a cheap light meter. I will try to perform a bit of a test and see if I can measure the light output from my headlamps and then compare to some others. My only problem is that most of the people I know only have either old halogens, or cool blues. So it's gonna be a bit of a indicative test only...

I'll try to remember to do that tonight and get back to you with results...

[JT]

I'd just pick that as good luck, my factory 35watt yellow foglamps get people flashing their lights at me - they soon stop when I get them with 460 watts of high beam

No, it's all about the angle as Matt states. I can clearly see the beam is low enough on dip but becase there is so much light with the more powerful bulbs, everything gets illuminated alot better. On full beam I can see a give way sign reflecting over 800m away

[matt dunn]

And the mystery continues. Where's Ccooby Doo when you need him...
I think there's a strong link between Hella and Philips. They both market near identical bulbs. Heck the adverts are even REALLY similar.

Phillips make Hella bulbs.

Phillips convinced hella to advertise the phillps name as much as the hella name, so hell did a lot of Phillips branded advertising,

and now phillips have branched out and marketed there own bulbs in there own packaging in competition with hella.

From what I understand.

[Perky]

That seems to be about right. We have noted that the Hella xenon bulbs, at least, seem to be made by Philips and are identical to the Philips branded ones. They are separate companies though and Philips-branded bulbs were always available overseas. Philips's website refers to Hella as a customer and a key partner -- for example, both companies are part of the FlexRay Consortium that determines standards for steer-by-wire etc. Philips has a similar relationship with Stanley Lighting which I believe is more closely connected with Hella. The light fittings on my Toyota are branded Stanley.

As for the Cool Blue issue:

What I'll do. I have a cheap light meter. I will try to perform a bit of a test and see if I can measure the light output from my headlamps and then compare to some others. My only problem is that most of the people I know only have either old halogens, or cool blues. So it's gonna be a bit of a indicative test only...

That would be interesting though, as you say, it's difficult to set controls.

On the other hand, I researched this on the internet some time ago and there are quite a few objective tests out there that show blue-tinted bulbs are dimmer. Unfortunately the most thorough I saw were carried out by the British magazine AutoExpress and they seem to no longer have them online. Maybe they are about to do another test. Actually the brightest bulb they tested was blue, albeit a xenon one-- from memory it was an Osram one that I have not seen available here. All the other tinted bulbs were dimmer than the best clear xenons. You do not need a test however to prove that a tinted bulb always has less output than the same bulb without the tinting.

But objective testing of output does not settle the issue of how the light is percieved. The AutoExpress tests also tested range -- the perception of which will not depend on colour -- and found the blue bulbs wanting. From what I have read there seems to be no reason to think that any greater perception of brightness from blue lights is associated with better vision.

Here is one discussion on the web.

http://www.danielsternlighting.com/tech ... d/bad.html
http://www.danielsternlighting.com/tech ... /good.html
http://www.danielsternlighting.com/tech ... white.html

It does not give scientific references but seems to be well informed and is consistent with other things I have read. It does suggest that the upper limit for bulb brightness is legal rather than technical but that boosting blue bulbs to be as bright as legal untinted bulbs greatly shortens the life of the filiment. The Hella Cool Blues are not boosted; they are merely tinted standard bulbs.

Here is an objective test of some bulbs that are different from those we are discussing:
http://www.overboost.com/story.asp?id=102

Note that in all this, I am not saying that some blue bulbs (those made by the big companies) might not be adequate, or that people shouldn't use them, merely that they are not the brightest bulbs available and I doubt that there is any benefit from them.

[Bahamuth]

I use 170/150 H4s mega white, and I use relay to boost the power. I think it's bright enough, or sometimes it just too bright and other thought I'm using highbeam =( then realised when I put the highbeam on (it's great on total dark place because it just illuminated everything in front of me but then I think its too dangerous on normal road since the other driver won't be able to see anything I guess).
So far I couldn't find the relay cable here, but I guess it can be easily made.
Now I change my lightbulb to 150/130 (I can't remember exactly) sort of dimmer but it give out mainly greenish colour with red, orange, yellow, blue colours too.

[Stealer Of Souls]

Well. Was too lazy over the weekend to do a test. I'll try to do it tonight when it gets dark.
The only thing this will give us is an emperical value for the output from the CBs, and then we can say exactly hwo much dimmer it is!

I hear what you're saying about the CBs and brightness and perception. Makes me wonder if Hella didn't boost the output to give the eqv to a 55/60W standard even with the blue filter. The life span of a CB is less than that of a halogen or Xenon... I just assumed it was due to something like higher heat retention due to the filter...


Results tomorrow??

[Perky]

The life span of a CB is less than that of a halogen or Xenon... I just assumed it was due to something like higher heat retention due to the filter...

Well I dare say that's possible too. I'll admit I'm just assuming that the CBs aren't boosted by running the filament hotter, for two reasons:

1)Hella describes their output as 'similar' to standard -- if they were brighter, or even as bright as standard I'm sure they would say so.

2)The safe way to run the filament hotter is to add some xenon to the halogen in the bulb. Again, you'd expect them to mention this, and in any case this is what the Xenon Ultras are for.

Something-else worth noting is that there are no doubt plenty of variables here that we have not considered. I don't know what the manufacturing tolerances are like for bulbs but perhaps you got very good Cool Blues, or very bad Xenons, or both. Perhaps plugging in the new bulbs cleaned some corrosion off the connectors. Perhaps there is some synergy between the shape of the CBs and the geometry of your headlights, etc.

My money would still be on the Cool Blues merely seeming brighter.

[wde_bdy]

1 = relays
2 = battery connection
3 = connection to standard light plug
4 = new plugs to bulbs
5 = earth

This is the kit I'm using to boost up my standard bulbs, will also allow me to uprate bulbs later without worrying about the factory wiring. Should be pretty easy to make your own if you can get hold of the plugs.

Callum

[Stealer Of Souls]

Yep.
My moneys on my CB just seeming brighter...

Well. A rather unscientific test, against much older bulbs, with only crude controls in places say that...
My less than one month Cool Blues are brighter than some two year old Artic Blues, some ancient halogens, and some one yearish old factory corolla lights (2004? work car).
I tried to get then all so that the top of low beam cut off pattern was just illuminating the sensor... Yep about as accurate as the latest govt budget...
I think the answer lies in that Cool Blues I reckon are in fact Xenons with the filter. And therefore will produce more light than a Halogen, but less than a Xenon. The rest is all perception. The whiter light is more perceived by the human eye making it appear as if there was more light. The reflectivity off of signs is real, and will have something to do with the materials of the signs I guess.

This has all peaked my interest, and I'm not planning to try and develop a slightly more scientifically sound test to see if it's possible to get a comparison...

[Perky]

Good on you for getting your hands dirty with an actual experiment!

As you say, it's difficult to draw conclusions with so many variables uncontrolled, but this does at least suggest that the filament in the CBs is running hotter to compensate for the filtering. And I guess that this would explain their shorter life. (Is your impression of shorter life based on personal experience, by the way?)

As for the reflectivity, I'll just note again that there is nothing in the output of the filtered bulbs that is not in the output of the unfiltered bulbs -- so nothing more to reflect. I guess if the CBs really are brighter than their direct competitiors ...

I may be wrong about this but I seem to remember that when Narva released their Arctic Blues, the press release I read in a magazine (prob. Driver) said that they were tinted versions of their plus30 bulbs -- which are xenon bulbs, though not their brightest. This isn't mentioned on their website so either I'm making it up or they may not see it as a point worth marketing. In which case, maybe Hella sneak some xenon into the CBs and don't mention it.

[Stealer Of Souls]

I think you're right on the bulbs being originally like +30s or +50s. I'm sure I saw that about the Hella ones too(+50s)! But I can't find it now!

Yeah. The CBs shorter life span is from experience. I seem to go through a pair of bulbs every two years (but I do drive with them on all the time). But my friend has also experienced the same shorter life span. Others who've replaced their (CB) lights with halogens or xenons definitely get more life out of the replacements.

Isn't there something in light (wave/particle) theory about attenuation/diffraction at the wavelength that says the whiter light will go further? Or am I imagining another physics lesson i slept through?

[Perky]

Well, I'm sure I'll quickly get out of my depth here. But as I've said, remember that the filter subtracts light from the original output; it does not add any. Specifically, the blue filter cuts out longer wavelengths, at the red-orange end of the spectrum, and lets through the shorter, bluer wavelengths. So it is not possible for the filtered light to travel further, or reflect more than the unfiltered light. Everything that is in the filtered light is also in the unfiltered light.

It is true that the absorption of light in a medium depends on its wavelength, so presumably some colours do travel further than others in air. But if this made a significant difference over ordinary distances you would see the colour of a beam of light change over its length - not to mention weird effects from distant streetlights or even daylight.

There is also diffraction (bending of rays around objects) of light in the atmosphere but this is not significant over short distances. In any case, shorter wavelengths, at the blue end, are diffracted far more than longer wavelengths -- which is why the sky is blue. So if there were any effect from this it would cause bluer light to lose intensity quicker than longer wavelengths -- which is why sunsets are red. I think one of the web sources I cited suggests that diffraction of blue/white light is why it is associated with glare from headlights, but I doubt this explanation as the distances are so short.

[Stealer Of Souls]

Well. There's another physics lesson i slept through...