Hi Mid-life.
Believe me, I'm not trying to argue with you at all. I think it was your post that made me go hunting, because when I went to price the bulbs after reading it, I got so confused by all the marketing stuff that the different brands used.
I got a little bent out of shape when someone dismissed Amsoil for not being technically fully SAE certified, because I have full faith in the quality of the Amsoil product, and have read enough data about the tests their oil goes through to believe their claims. My point being that
please don't think I'm being argumentative here by posting these particular quotes. I've seen some of the bulbs out there, and to my eye they also appeared whiter and presumably brighter. But, having an 8 hour 12-8 shift gave me plenty of time to read everything this guy wrote, and I came away from it less willing to believe my eyes.
From the link: (Rude tone his, not mine.)
<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
It is a mistaken notion that "whiter" and "yellower" qualities in the white light of a headlamp have any direct link to the amount or usability of the light. PIAA capitalizes on that mistaken notion to sell their bulbs. The "higher light color temperature" trumpeted by PIAA is created by a purplish-tinted glass bulb globe. It's not a dichroic coating like the "diamond blue" junk, but it is a tint, and as such physically must subtract from the available light. Remember, color temperature is independent of the amount of light, and there is absolutely *zero* evidence that light of a higher color temperature is better than light of a lower color temperature for driver performance at night. A 4-watt flashlight bulb dipped in the purple coating applied to Piaa "Superwhite" bulbs would look "whiter", but produce less light. And so it is with these headlamp bulbs.
People seem to have the notion that the eye is more sensitive to light of higher color temperature. This is probably as a result of claims made by car salesmen trying to sell HID headlamps more than anything else; it's false. The eye is not more sensitive to the blue cast created by the subject bulbs. There have been several studies done showing improved driver performance (due to improved vision at night) with headlamps of LOWER color temperature (less blue, more yellow). Color perception is much better under lower color temperatures (within the IEC "white" boundaries, of course), and the acuity of the human eye is really quite lousy under light colors that even begin to approach "blue".
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>
<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>When a bulb with such a modified filament stack is placed in a headlamp, the different dimensions of the filament alter the beam pattern. In most US-specification headlamps, what this does is reduce the size of the central "hot spot" of the beam and put more light in it, while taking away light above, below, to the left and to the right of the hot spot. Then the PIAA marketeer comes up with his light meter, sticks it in the hot spot of the beam, and says "Nifty! The hot spot is almost as bright as it would be with an 85W bulb!" and rushes off to order-up a new batch of boxes festooned with "55W = 85W" banners. Then Mr. Consumer comes along, plunks-down some $70 (!!) for a pair of these bulbs, puts them in, and though his headlamps look "whiter", he has just screwed himself.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>
<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>The output spectrum of halogen headlamp bulbs includes *very* little light in the blue frequency range. These blue bulbs have a filter coating on them that allows only the blue frequencies through the filter. Because very little light is produced by a halogen bulb in this range in the first place, it is only this very small amount--a tiny fraction of the total amount of light produced by a halogen bulb filament--that ever reaches the road. This can be confirmed this with a good-quality non-chromosensitive light meter; even a very apparently-bright blue bulb actually throws very little light.
Recent tests by the US Department of Transportation's Office of Crash Avoidance Standards found that a standard-wattage 9004-type blue headlamp bulb reduced the road lighting ability of a standard headlamp by 67%, and increased glare for oncoming and preceeding trafic by 33%.
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Man, believe me when I say I'm not trying to change your mind. But before you dismissed these articles, I wanted you to see the specific parts where he talks about whiteness, blue light, and PIAA.
No poking with a stick intended,
Joe
