Zenmervolt
Elite member
- Oct 22, 2000
- 24,514
- 44
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No, they don't work better. It's an illusion. The blue tinted bulbs put out less light, and produce more glare. The "improvement" is simply that you see more glare so your brain thinks things are brighter when, in fact, they are not and you're actually getting less light.
http://www.danielsternlighting.com/tech/bulbs/superwhite/superwhite.html
CLAIM: "Our bulbs produce the whitest and brightest light on the road!"
REALITY: "Brightness" is like "Loudness". It's a subjective perception. Is Metallica " louder " than Bach? Most people would say so. That's why audiologists use an objective measurement, Sound Pressure Level, rather than subjective quantities like "volume" and "loudness". And so it is in the science of light. "Bright" and "Dim" are subjective perceptions. Intensity, measured in any of several precisely-defined and scientific ways, is the only real way to gauge or compare output of a light source or performance of a lamp equipped with a light source. A 4-watt flashlight bulb dipped in the purple coating applied to these tinted headlamp bulbs would look "whiter", and might look "brighter", but would produce less light. And so it is with these headlamp bulbs.
The reason why the scam fools people into thinking their headlamps really work better has to do with the interaction of light that is tinted blue (to any degree) with the human eye. This kind of light has been shown in rigidly-controlled scientific studies to create almost 50% more glare than untinted light from a bulb with clear glass. But there's no 50% increase in seeing to go along with the extra glare; there's no increase in seeing at all, and in most cases there is a moderate reduction in actual seeing light. More glare, less seeing: Everybody loses.
CLAIM: Many of these bulbs are sold with claims of specific "color temperature" (e.g. "5000K"). Often, these ratings are accompanied by text to the effect that higher color temperatures are "close to natural daylight".
REALITY: Color Temperature is a real measure, but it is being improperly used to claim improved seeing. Legitimate bulb manufacturers do catalogue the color temperature of their products in technical literature not usually distributed to consumers, because scientists and engineers can use it as a convenient proxy indicator for filament luminance. But it has no predictive value for the performance of an automotive headlamp, nor does it indicate how well you'll be able to see. The idea being sold with these "Kelvin ratings" is that the light is closer to natural sunlight. As with many sales claims, there is a small kernel of truth here, but it's cancelled out by the smoke and mirrors. Noonday sunlight does have a much higher color temperature than most uncoated headlamp bulbs, but there are a great many other differences between sunlight and headlamp light, as well. Not only that, but the Color Temperature rating is really valid only at extremely high light intensity, such as that produced by the sun. At the lower intensities produced by most electric lamps including headlamps, the rating no longer says much about the light, but only allows a limited, referential comparison of different light colors. The tinted bulbs' poor imitation of the color of sunlight does not mean that the headlamp output is "just like sunlight", or anything even close. As with the wattage equivalence claims discussed above, a color-based comparison is being used to imply an intensity and seeing-ability comparison that does not exist.
ZV
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