quote: Xtravisions claim they last twice as long...
Sorry, I got confused with the Siverstars (US). The Silverstars are known to burn out a lot faster than the non coated ones since the filaments are overdriven. The Xtravision's last as long if not longer than the regular bulbs. Better filament design/etc...
quote: So are you guys saying that the Xtra Vision bulbs are really brighter than S.Stars? Has anyone had them both to see that Xtra Vision is better? or do you guys THINK the Silverstars are less bright because they have the blue tint?
What you guys say about US/Euro SS is logical, though:
I checked Sylvania website, and in their FAQ section they say that the US Xtra-vision is more similar to EUROPEAN Silver Stars!
should get the XtraVision next time..
are they also cheaper than the S-stars?
"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.
The Xtravision blubs are cheaper than the Siverstars and can be found at Wal-mart for under $20 for the pair. I've had them both and the Xtravision's are far better for less money. Don't feel bad though, everyone gets tricked once in a while.
Some people feel that "whiter" light than is produced by a clear halogen bulb is better. Some people prefer the appearance of the headlamp, though its operating appearance with these legal "blue" bulbs differs very little from the appearance of a headlamp operating with a regular clear bulb. And then there are the True Believers, who ascribe all kinds of magical (and imaginary) benefits to "whiter" light.
Some companies (PIAA...) even capitalize on this by claiming that their "55W bulbs are as bright as 85W" bulbs, among other nonsensical claims. Here's how this claim works: Higher-wattage bulbs appear whiter than lower-wattage bulbs. Think of the time you replaced a 60W bulb in your home with a 100W bulb. So the idea with these "blue" filtered bulbs is to have a lower wattage bulb that produces a similar light color to a higher wattage bulb. However, there is no such a thing as "something for nothing". Light color similarity does not mean you're getting more light, or better quality light — just that the light is of a slightly different color.
In fact, you could be getting less light from such a bulb than from a regular clear bulb, and here's why: A blue filter removes nonblue components of the light passing through it. Halogen bulbs produce very little light in the blue frequency range. When you put a blue filter on the bulb or lamp, you are reducing the amount of usable light that gets from the glowing filament to the reflector, to the lens and from there to the road. Prove it to yourself using nothing more than the windshield in your car...drive towards a yellow-orange Sodium vapor street light and watch the light as it shines first through the clear portion of the windshield, then through the blue strip at the top. Up there through the blue, it certainly looks "whiter"...but it's also dimmer. If a bulb's sales material focuses on the color of the light rather than the amount of light, you should ask critical questions about the amount of light the bulb produces before choosing to use it.
The Osram-Sylvania Cool Blue (and its equivalents the Narva RangePower Blue, the Philips BlueVision, etc.) produce *LEGAL* light output. But there's some wiggle room in the bulb standards that permit two bulbs of the same format to put out significantly different amounts of light, and yet both still be legal.
For illustration of the principle, take a standard HB5 (9007) bulb, which is legally required to produce 1000 lumens of light from the 55W low beam filament, plus-or-minus 15 percent. That means that in order to be legally certifiable as conforming to FMVSS108, a 9007 bulb in the low beam mode must produce between 850 and 1150 lumens. Most folks want to see better at night, not worse, and the way to do that is to use bulbs that produce the maximum legal amount of light. I'd rather have my bulbs producing 1150 lumens instead of 850, how 'bout you?
So now, where do these legal "blue" bulbs fit on our 850 to 1150 lumen range? It's not possible to say without access to bulb-performance data usually considered proprietary by bulb manufacturers. About all that can be said is that they're safe, they're legal, they're not dangerously poor performers like illegal blue bulbs are, nor are they a scam like the much-hyped SuperWhite bulbs are ... but they do not give a performance increase as such.
The manufacturer optimizes the bulb's efficacy through filament and gas-fill technology, so that the uncoated bulb performs up near the top end of the allowable output range, or even slightly above the maximum allowable output. But the bulb is blue, which "steals" some of the light. If the bulb is designed to produce within the legal light level without the blue, the presence of the blue bulb will drop the output closer to the bottom end of the allowable output range. If the bulb is designed to produce slightly over the legal light level without the blue, then the bulb will perform nearer the middle or towards the top of the legal range. Here again, though, we can't have something for nothing. Not only are there legal limits on light output, but also on power input. These wattage restrictions prevent bulb manufacturers from simply ramping-up the bulb wattage in order to have a bulb that produces high-end output even with a blue filter. It took Osram-Sylvania, Philips, and other major-name bulb makers quite a bit of research and development to produce blue filters that would not drop the bulb output below the legal minimum while still altering the appearance of the operating headlamp enough to appeal to consumers after a "whiter" appearance to their headlamps.
Part of the impetus for the development of these bulbs was for the makers of good-quality bulbs to take away a portion of the dangerous "crystal blue" type bulb sales and offer consumers desiring a different headlamp appearance a legal and safe product. The retail-level marketers have an easy sell here; Pep Boys offers a "Cool Blue Upgrade" service for fifty bucks, for instance. And there are always going to be people lining up to offer glowing testimonials about how much better they think they can see with these bulbs. But can they really?
There's no conclusive evidence that the type of light produced by this sort of bulb actually allows drivers to see better than the type of light produced by a regular, clear bulb. And there've been no studies on the effect of this type of light upon seeing and glare in bad weather, for instance. Can you see better with this sort of bulb? Perhaps, and perhaps not. Some people seem to think so. But what if that's exactly the problem — they think they can see better than they actually can? There've been no studies to determine exactly how dangerous it is to think you can see better than you really can, but it can't be very safe.
It should be mentioned that while these are critical questions that ought to be asked, they are academic to some degree as long as you stick to the product of a reputable manufacturer, such as Osram-Sylvania, Philips, or Narva.
For those who want the best possible performance from their headlamps and are more concerned with their ability to see rather than the appearance of their headlamps, the major bulb companies offer optimized bulbs WITHOUT the light-stealing blue coloration. Sylvania Xtravision (in the pink-and-black package), Osram Super and SilverStar(outside North America only!); Philips High Visibility (North America), Premium and Vision Plus (outside North America); Narva RangePower are the ones to look for.
Osram, the well-established German lampmaker, sells a line of automotive bulbs they call "SilverStar". These are Osram's top-of-the-range headlamp bulbs, equivalent to Philips VisionPlus and Tungsram Megalight Premium. They produce the maximum legal amount of light while staying within legal power consumption limits. They have clear glass.
Osram bought the well-established American lampmaker Sylvania in the early 1990s, so Osram is now Sylvania's parent company. Sylvania also sells a line of automotive bulbs they call "SilverStar", but it's not the same product at all. These bulbs have a blue coating on them. Light output is of legal levels, but as with all blue-filtered bulbs, you do not get more light from them. The Sylvania SilverStar bulbs have a very short lifetime, because the filament is selected so as to be overdriven. This is necessary because the blue filtration coating "steals" so much light that only an overdriven filament can push enough light through the filter to be legal. The Sylvania SilverStar bulbs are also priced quite high. This is not because they cost a lot to make, and not because they're based on some exotic new technology. It's because the goal with this product is to take market share away from other overpriced bulbs like the PIAA line.
For best headlamp performance and best value, choose only bulbs with clear glass.
