I received the following not-to-complex question from a customer:
What is the Kelvin temperature of the Vosla H4 bulb?
I wasn't positive so I thought I would ask Daniel Stern, our automotive lighting consultant and internationally recognized expert. Quick question, quick answer, right? Hang on.... Here's Daniel's response:
Before I give you the numerical answer, I need to explain stuff, because this question almost always comes from those who have been led badly astray by marketing BS.
While colour temperature ("kelvin rating") is a real thing, its use in the advertisement of automotive light sources is almost entirely fraudulent. Outside of a small range created by different surface luminance characteristics of different legitimate bulb designs (about 3050K to 3450K), higher-CCT light mimicked by blue- or purple-tinted bulb glass (for example), contrary to misinformed and disinformed advertising hype, is not "closer to natural daylight" and does not help you see better in any way. All it does is change the appearance of the operating headlamp, increase glare, and reduce the amount of usable light reaching the road.
Any of the bulbs claiming to produce "extra white" light (or super white, hyper white, platinum white, metal white, xenon white, etc) as its main promotional "benefit" is best avoided. It doesn't matter whose name is on the bulb—Sylvania SilverStar/Ultra or ZxE, Philips BlueVision or CrystalVision, Wagner TruView, anything from PIAA or Hoen,, Nokya, Polarg, etc.—all the same scam. They have a blue-tinted glass, which changes the light color a little, but blocks light that would reach the road if the glass weren't tinted, so they give you _less_ light than ordinary bulbs (not more). To get legal-minimum levels of light through the blue glass, the filament has to be driven very hard so these bulbs have a very short lifespan, and there's nothing about the tinted light that improves your ability to see—the opposite is true (less light = less seeing, no matter about the tint). Sylvania got spanked to the tune of thirty million(!) dollars for false and misleading "upgrade" claims for Silver Star bulbs (see https://www.ledinside.com/news/2014/..._false_ad_suit )—and those are among the least-bad of an overall bad product category, so the math kind of does itself.
With all that said, a standard H4 bulb is about 3150K on low beam and 3250K on high beam. The Vosla H4 +190 is about 3350K to 3400K on both beams.
Daniel is what you might call serious about his craft. And he is a very generous man (and a good friend). He is constantly trying to educate me on the science of automotive lighting. Sometimes I feel like I'm in graduate school. Anyway, now you know all about the kelvin temperatures of bulbs - unless you would like Daniel to go into more detail. j
Cheers,
John
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