Is it worthwhile at all to swap the fogs for those yellow ones?
12-04-2006, 11:45 AM
#21
AudiWorld Super User
Dangerous, illegal, blue headlight bulbs...
Dangerous, illegal, blue headlight bulbs
What's All The Fuss?
Various companies and individuals are selling halogen headlamp bulbs with blue or purplish-blue glass. There are lots of spurious claims made for these bulbs. They're falsely advertised as "Xenon bulbs" or "HID bulbs", the blue glass is claimed to "force the bulb to perform at a higher level", and there are seemingly endless amounts of pseudoscience aimed at enticing buyers who want better performance from their headlamps. In fact, these bulbs reduce headlamp performance while increasing dangerous glare.
How and why are blue bulbs dangerous?
Many of them degrade roadway safety," both yours and other drivers'. Some of them can be physically hazardous. Here are the nuts and bolts of why blue bulbs are a bad idea:
White light is made up of every color of light mixed together. But the colors are not all present in equal amounts. The output spectrum of filament bulbs, including halogen headlamp bulbs, includes a great deal of red, orange, yellow and green light, but very little blue or violet light. Blue bulbs have colored glass (or a filter coating applied to clear glass) that allows only the blue light through the filter -- this is why the bulbs appear blue. Because very little blue light is produced by a halogen bulb 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.
Blue and violet are the shortest wavelength/highest frequency colors of visible light, and, as such, they scatter the most readily. This is why the sky is blue rather than any other color from the sun's white output spectrum. Blue light doesn't just scatter most readily in the sky, but also in the eye. To observe this effect, try this informal experiment: Next time you see a dark blue storefront sign or a row of blue airport runway landing lights after dark, notice how blurry the edges of the sign or landing light appears compared to adjacent lights or signs of different colors. Decades ago, hot rodders would install "blue dots" in their cars' taillamps. These small bits of blue glass cause the taillamps to appear not red with a blue dot in the center, but rather pinkish-purple, because the observer's eye easily focuses on the red but has trouble with the blue, which remains out of focus and appears to tint the entire area of the red light.
How can there be more glare if there's less light?
Informal 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 traffic by 33%. This apparent contradiction arises because of the way the human eye handles light of different colors. The short-wavelength colors (blue, indigo and violet) are very difficult for our eyes to process and focus on.
Compared to uncolored bulbs, Blue headlight bulbs are able to produce more glare with less light because of the difference between the "signal image", which is what an observer sees when looking at an illuminated headlamp, and the "beam pattern", which is the light viewed from behind the headlamp facing forward, as by the driver of a vehicle. In order for headlamp light to be used by the driver, the light must travel forward from the headlamp to an object, bounce off the object and return to the driver's eyes. As light travels through the atmosphere, it spreads and diffuses according to the Inverse Square Law: The intensity drops as 1/(distance)2. That is, a given headlamp will illuminate an object 2 feet away with 1/4 of the intensity found at the front face of the headlamp, an object 3 feet away with 1/9 of the source intensity, an object 10 feet away with 1/100 of the source intensity, and so on -- and then this loss is redoubled because the light must travel back to the observer's eyes. Remember that the blue filtration prevents the bulk of the light being produced from reaching the road, so the light "stealing" effect of the Inverse Square law becomes greatly magnified: Less light by which to see.
On the other hand, light travels directly from the headlamp to the eyes of the oncoming observer, so the "back to the driver's eyes" redoubling of the Inverse Square law does not take place:More glare. Therefore, for any given distance between the headlamps and the observer, there'll be considerably more light to cause glare than there'll be to allow the driver to see More glare.
Note that some types of "blue" headlamp bulbs are actually legal and not necessarily unsafe; you can read about them here
Does the scattering tendency of blue light affect headlamp performance and road safety in other ways?
Yes, in two ways:
Because blue light scatters very readily in the human eye, casting a beam that's blue-tinted by any amount in a rainy, foggy or snowy environment causes increased perceived backglare for the driver of a car equipped with blue headlamp bulbs.
Also, blue light per secreates increased glare for oncoming traffic. That's because blue light does not trigger a strong pupil-closing response in human eyes. It is yellow light that stimulates the human eye most strongly to constrict the pupil. Due to the comparatively weak pupil response to blue light, the human eye is very glare-sensitive to a blue signal image. With the yellow light filtered out by the blue bulb and prevented from reaching the observer's eyes, the pupils remain wider open than they should, and the eyes are hit with a blast of difficult-to-process blue light.
Isn't the same amount of blue light reaching the observer's eyes whether or not the bulb is blue?
Although the same amount of blue is emitted by a halogen bulb whether it's got a blue-filter coating or not, in the "no filter" case, the remainder of the output spectrum--consisting largely of yellow light--triggers a pupil-closing response in the eyes of oncoming traffic, helping to reduce the short and long term effects of headlamp glare. This glare-protection response is severely compromised when the oncoming signal image is blue.
What about real Xenon headlamps that are blue from the factory?
Genuine arc-discharge (also called metal-halide HID) headlamps run with a very purplish-white character similar to an electronic photoflash, because the same technology is at work--an electrical arc jumping through an atmosphere of Xenon gas. But despite the purplish appearance, this light is actually white with a discrete blue component. That is, most of the light from a Xenon headlamp is white, and there is also blue.
The emerging understanding is that there may be not only a split between the glare-sensitive and non-glare-sensitive amongst the populace, but also among those particularly sensitive to blue, violet and/or near-UV light, and those not particularly sensitive to these wavelengths--with these sensitivities NOT necessarily being linked! This helps explain why some find High Intensity Discharge headlamps menacingly painful and consider them hazardous to share the road with, while others consider them no problem at all.
Researchers are currently working on tweaking the output spectrum of automotive HIDs to eliminate the useless-for-seeing spike in the high blue which causes this reaction in blue-sensitive individuals.
The blue signal images from HID and from blue-tinted halogen lamps arise from two wholly separate phenomena, and therefore can't be directly compared. The main thing is to keep in mind that the blue signal image of an HID headlamp is a throwaway byproduct of a light source that also emits a great deal of white light, while the blue signal image of a blue-tinted halogen lamp is the meager blue ouput left when all the rest of the light has been trapped by the filter.
Are these blue bulbs illegal?
US, Canadian, European and Japanese regulations all call for "white" light. There is no one specific light color that is defined as "white" light; rather, there is a large range of output spectra that are considered "white", and the "white" light is permitted to exhibit visible tints of blue, yellow, green, orange or red. Various regulatory bodies are considering narrowing the "white" standard so that it is less permissive of blue tinting. Such has been the spread of blue headlamp bulbs that many police agencies have purchased in-field beam color testers--they use these on headlamps that look too blue to be legally considered "white".
What about blue-tinted headlight bulbs that I found at a local auto parts store, or on the internet? They're sold as being "DOT Approved". Are these legal?
Probably not. There's no such thing as "DOT approved". DOT does not "approve" products as the European regulatory body does. Rather, the manufacturer of an item of motor vehicle equipment is legally obligated to self-certify that his product complies with all applicable regulations. For some items of equipment, such as headlamp bulbs, the certification takes the form of a "DOT" marking on the bulb base. However, there is no legal obligation for the manufacturer to submit his product for government testing before applying the marking, and many companies go ahead and apply the marking even to bulbs that do not comply with the law. The relevant regulations (US Federal Motor Vehicle Safety Standard 108, Canadian Motor Vehicle Safety Standards 108 and 108.1, and ECE Regulations 8, 20, 37, 98, 99, 112 and 113 all call for "white" light, defined as discussed above, so the statement of DOT compliance itself is false for a bulb that emits a light color obviously different from "white".
Why is there even a market for bulbs like this, if they're so illegal and unsafe?
Many motorists have been confused by marketing claims for the blue bulbs, which falsely and incorrectly equate the blue bulbs' performance with the very expensive arc-discharge ("Xenon") headlamps found on top-line luxury cars. They have been led to believe that by replacing their car's headlamp bulbs with the blue-coated bulbs, their headlamps' performance will be increased. In fact, quite the opposite is true; their headlamps' performance is decreased by the use of blue bulbs.
There is psychology at work in the marketplace, as well. Many of these blue bulbs are sold at very high prices in extremely attractive packaging. It is well known to marketers that the motorist who pays $35 or $45 or even $85 for a set of "special high performance" bulbs will probably perceive a performance improvement even if there is actually none.
Some motorists believe that the blue light makes their car look "cool". This would fall into the same category as the dark plastic headlamp and taillamp covers that are snapped-up by certain drivers for their appearance "enhancement" value, despite the fact that these covers, like the blue bulbs, are illegal and dangerous.
What about bulbs sold as "Xenon" that have clear glass?
Probably no word is used to refer to so many different automotive lighting products as "Xenon", which is an elemental gas. A "Xenon lamp" is a gas-discharge (or High Intensity Discharge)-sourced lamp without a filament. It produces light by maintaining an electrical arc in a highly pressurized environment containing elements--including Xenon&mdashto make the arc emit a great deal of light.
But, Xenon also has a place in lamps with filaments. The addition of a certain proportion of Xenon to the atmosphere in a halogen bulb allows the use of a filament designed to burn hotter, thereby emitting more light, without the rapid burnout of such a filament that would occur without Xenon. But it's not a case of more being better; beyond a certain percentage, Xenon actually reduces the lifespan of the filament.
Halogen headlamp bulbs containing Xenon, in general, are not a gimmick or a scam, if they've got clear glass and are produced by a reputable company. All of the newest bulb designs being produced for new headlamps--such as the H7, H9 and H13 bulb size--include Xenon. Results have been good, with the H7 achieving a higher luminous flux (amount of available usable light) from a given wattage than was achievable with halogen bulbs that didn't include Xenon. So after a few years' experience with H7s, the manufacturers have moved to increase the performance of older, traditional bulb types. One of the techniques used to get such an improvement is to add Xenon to the bulb's atmosphere. There are other valid techniques as well, and not every bulb containing Xenon (or advertised as containing Xenon) is necessarily a performance upgrade.
What's All The Fuss?
Various companies and individuals are selling halogen headlamp bulbs with blue or purplish-blue glass. There are lots of spurious claims made for these bulbs. They're falsely advertised as "Xenon bulbs" or "HID bulbs", the blue glass is claimed to "force the bulb to perform at a higher level", and there are seemingly endless amounts of pseudoscience aimed at enticing buyers who want better performance from their headlamps. In fact, these bulbs reduce headlamp performance while increasing dangerous glare.
How and why are blue bulbs dangerous?
Many of them degrade roadway safety," both yours and other drivers'. Some of them can be physically hazardous. Here are the nuts and bolts of why blue bulbs are a bad idea:
White light is made up of every color of light mixed together. But the colors are not all present in equal amounts. The output spectrum of filament bulbs, including halogen headlamp bulbs, includes a great deal of red, orange, yellow and green light, but very little blue or violet light. Blue bulbs have colored glass (or a filter coating applied to clear glass) that allows only the blue light through the filter -- this is why the bulbs appear blue. Because very little blue light is produced by a halogen bulb 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.
Blue and violet are the shortest wavelength/highest frequency colors of visible light, and, as such, they scatter the most readily. This is why the sky is blue rather than any other color from the sun's white output spectrum. Blue light doesn't just scatter most readily in the sky, but also in the eye. To observe this effect, try this informal experiment: Next time you see a dark blue storefront sign or a row of blue airport runway landing lights after dark, notice how blurry the edges of the sign or landing light appears compared to adjacent lights or signs of different colors. Decades ago, hot rodders would install "blue dots" in their cars' taillamps. These small bits of blue glass cause the taillamps to appear not red with a blue dot in the center, but rather pinkish-purple, because the observer's eye easily focuses on the red but has trouble with the blue, which remains out of focus and appears to tint the entire area of the red light.
How can there be more glare if there's less light?
Informal 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 traffic by 33%. This apparent contradiction arises because of the way the human eye handles light of different colors. The short-wavelength colors (blue, indigo and violet) are very difficult for our eyes to process and focus on.
Compared to uncolored bulbs, Blue headlight bulbs are able to produce more glare with less light because of the difference between the "signal image", which is what an observer sees when looking at an illuminated headlamp, and the "beam pattern", which is the light viewed from behind the headlamp facing forward, as by the driver of a vehicle. In order for headlamp light to be used by the driver, the light must travel forward from the headlamp to an object, bounce off the object and return to the driver's eyes. As light travels through the atmosphere, it spreads and diffuses according to the Inverse Square Law: The intensity drops as 1/(distance)2. That is, a given headlamp will illuminate an object 2 feet away with 1/4 of the intensity found at the front face of the headlamp, an object 3 feet away with 1/9 of the source intensity, an object 10 feet away with 1/100 of the source intensity, and so on -- and then this loss is redoubled because the light must travel back to the observer's eyes. Remember that the blue filtration prevents the bulk of the light being produced from reaching the road, so the light "stealing" effect of the Inverse Square law becomes greatly magnified: Less light by which to see.
On the other hand, light travels directly from the headlamp to the eyes of the oncoming observer, so the "back to the driver's eyes" redoubling of the Inverse Square law does not take place:More glare. Therefore, for any given distance between the headlamps and the observer, there'll be considerably more light to cause glare than there'll be to allow the driver to see More glare.
Note that some types of "blue" headlamp bulbs are actually legal and not necessarily unsafe; you can read about them here
Does the scattering tendency of blue light affect headlamp performance and road safety in other ways?
Yes, in two ways:
Because blue light scatters very readily in the human eye, casting a beam that's blue-tinted by any amount in a rainy, foggy or snowy environment causes increased perceived backglare for the driver of a car equipped with blue headlamp bulbs.
Also, blue light per secreates increased glare for oncoming traffic. That's because blue light does not trigger a strong pupil-closing response in human eyes. It is yellow light that stimulates the human eye most strongly to constrict the pupil. Due to the comparatively weak pupil response to blue light, the human eye is very glare-sensitive to a blue signal image. With the yellow light filtered out by the blue bulb and prevented from reaching the observer's eyes, the pupils remain wider open than they should, and the eyes are hit with a blast of difficult-to-process blue light.
Isn't the same amount of blue light reaching the observer's eyes whether or not the bulb is blue?
Although the same amount of blue is emitted by a halogen bulb whether it's got a blue-filter coating or not, in the "no filter" case, the remainder of the output spectrum--consisting largely of yellow light--triggers a pupil-closing response in the eyes of oncoming traffic, helping to reduce the short and long term effects of headlamp glare. This glare-protection response is severely compromised when the oncoming signal image is blue.
What about real Xenon headlamps that are blue from the factory?
Genuine arc-discharge (also called metal-halide HID) headlamps run with a very purplish-white character similar to an electronic photoflash, because the same technology is at work--an electrical arc jumping through an atmosphere of Xenon gas. But despite the purplish appearance, this light is actually white with a discrete blue component. That is, most of the light from a Xenon headlamp is white, and there is also blue.
The emerging understanding is that there may be not only a split between the glare-sensitive and non-glare-sensitive amongst the populace, but also among those particularly sensitive to blue, violet and/or near-UV light, and those not particularly sensitive to these wavelengths--with these sensitivities NOT necessarily being linked! This helps explain why some find High Intensity Discharge headlamps menacingly painful and consider them hazardous to share the road with, while others consider them no problem at all.
Researchers are currently working on tweaking the output spectrum of automotive HIDs to eliminate the useless-for-seeing spike in the high blue which causes this reaction in blue-sensitive individuals.
The blue signal images from HID and from blue-tinted halogen lamps arise from two wholly separate phenomena, and therefore can't be directly compared. The main thing is to keep in mind that the blue signal image of an HID headlamp is a throwaway byproduct of a light source that also emits a great deal of white light, while the blue signal image of a blue-tinted halogen lamp is the meager blue ouput left when all the rest of the light has been trapped by the filter.
Are these blue bulbs illegal?
US, Canadian, European and Japanese regulations all call for "white" light. There is no one specific light color that is defined as "white" light; rather, there is a large range of output spectra that are considered "white", and the "white" light is permitted to exhibit visible tints of blue, yellow, green, orange or red. Various regulatory bodies are considering narrowing the "white" standard so that it is less permissive of blue tinting. Such has been the spread of blue headlamp bulbs that many police agencies have purchased in-field beam color testers--they use these on headlamps that look too blue to be legally considered "white".
What about blue-tinted headlight bulbs that I found at a local auto parts store, or on the internet? They're sold as being "DOT Approved". Are these legal?
Probably not. There's no such thing as "DOT approved". DOT does not "approve" products as the European regulatory body does. Rather, the manufacturer of an item of motor vehicle equipment is legally obligated to self-certify that his product complies with all applicable regulations. For some items of equipment, such as headlamp bulbs, the certification takes the form of a "DOT" marking on the bulb base. However, there is no legal obligation for the manufacturer to submit his product for government testing before applying the marking, and many companies go ahead and apply the marking even to bulbs that do not comply with the law. The relevant regulations (US Federal Motor Vehicle Safety Standard 108, Canadian Motor Vehicle Safety Standards 108 and 108.1, and ECE Regulations 8, 20, 37, 98, 99, 112 and 113 all call for "white" light, defined as discussed above, so the statement of DOT compliance itself is false for a bulb that emits a light color obviously different from "white".
Why is there even a market for bulbs like this, if they're so illegal and unsafe?
Many motorists have been confused by marketing claims for the blue bulbs, which falsely and incorrectly equate the blue bulbs' performance with the very expensive arc-discharge ("Xenon") headlamps found on top-line luxury cars. They have been led to believe that by replacing their car's headlamp bulbs with the blue-coated bulbs, their headlamps' performance will be increased. In fact, quite the opposite is true; their headlamps' performance is decreased by the use of blue bulbs.
There is psychology at work in the marketplace, as well. Many of these blue bulbs are sold at very high prices in extremely attractive packaging. It is well known to marketers that the motorist who pays $35 or $45 or even $85 for a set of "special high performance" bulbs will probably perceive a performance improvement even if there is actually none.
Some motorists believe that the blue light makes their car look "cool". This would fall into the same category as the dark plastic headlamp and taillamp covers that are snapped-up by certain drivers for their appearance "enhancement" value, despite the fact that these covers, like the blue bulbs, are illegal and dangerous.
What about bulbs sold as "Xenon" that have clear glass?
Probably no word is used to refer to so many different automotive lighting products as "Xenon", which is an elemental gas. A "Xenon lamp" is a gas-discharge (or High Intensity Discharge)-sourced lamp without a filament. It produces light by maintaining an electrical arc in a highly pressurized environment containing elements--including Xenon&mdashto make the arc emit a great deal of light.
But, Xenon also has a place in lamps with filaments. The addition of a certain proportion of Xenon to the atmosphere in a halogen bulb allows the use of a filament designed to burn hotter, thereby emitting more light, without the rapid burnout of such a filament that would occur without Xenon. But it's not a case of more being better; beyond a certain percentage, Xenon actually reduces the lifespan of the filament.
Halogen headlamp bulbs containing Xenon, in general, are not a gimmick or a scam, if they've got clear glass and are produced by a reputable company. All of the newest bulb designs being produced for new headlamps--such as the H7, H9 and H13 bulb size--include Xenon. Results have been good, with the H7 achieving a higher luminous flux (amount of available usable light) from a given wattage than was achievable with halogen bulbs that didn't include Xenon. So after a few years' experience with H7s, the manufacturers have moved to increase the performance of older, traditional bulb types. One of the techniques used to get such an improvement is to add Xenon to the bulb's atmosphere. There are other valid techniques as well, and not every bulb containing Xenon (or advertised as containing Xenon) is necessarily a performance upgrade.
12-04-2006, 11:46 AM
#22
AudiWorld Super User
Safe, Legal, Blue...But Are They Any Good?
Safe, Legal, Blue...But Are They Any Good?
What's the Scoop on "Extra White" Bulbs From Reputable Manufacturers?
You're asking about the current crop of bulbs, widely available in auto parts stores, with a blue absorption filter on the bulb glass, which is there to make the light look whiter. These bulbs are generally safe and legal, though not advantageous, to use in your car.
Some people feel that "whiter" light is better. Some people prefer the appearance of the headlamp when fitted with these bulbs. 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 pseudoscientific claims. Here's how this claim works: Higher-wattage bulbs of a given type generally appear whiter than lower-wattage bulbs. Think of the last 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 mimics the color of a higher wattage bulb, but not its performance. However, there's no getting something for nothing. The altered light color does not mean you're getting more light, or better quality light, just that the light is of a different color.
In fact, you get less usable 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.
But If That's True, Then How Come These Bulbs Have All The DOT and ECE Approval Markings Saying It's OK To Use Them On The Road?
The name-brand "extra white" bulbs mostly produce legal light output, true. But there's a lot of wiggle room in the bulb standards that permit two bulbs of the same format to put out significantly different amounts of 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 at 12.8v, plus or minus 15 percent. That means that in order to be legally certifiable as conforming to Federal standards, 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. On a dark road, I want 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? Most times, this information isn't available, for it's often made unavailable by bulb manufacturers. Some of the bulbs come with specification sheets giving a wattage and lumen rating, but these don't list actual output, they simply list the nominal specification contained in the Federal standard. The assumption they want you to make is that the bulb you're holding in your hand actually produces the nominal amount of light. In most cases, with blue glass, they don't. About all that can truthfully be said is that they're safe, they're legal, they're not dangerously poor performers like illegal blue bulbs are, but they do not give an actual performance improvement.
So If Blue Filtration Steals Light, How Do They Still Make These Bulbs Produce Legal Output With The Blue Filter?
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 reduce the output so it's 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 middleof the legal range. Here again, though, we can't have something for nothing.It took reputable 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. The cost? Bulb lifetime. The filament changes made to produce enough extra light that the bulb will still be legal despite the blue-filtration losses mean the filament's lifespan is shortened considerably.
Here's actual data for for output and lifespan at 13.2v for H1 bulbs. The numbers here are a composite of values applicable to the products of the three major manufacturers' bulbs. Each maker's product in each category is slightly different but not significantly so, and while the absolute numbers differ with different bulb types, the relative comparison patterns hold good for whatever bulb type you consider. Lifespan is given as Tc, the hour figure at which 63.2 percent of the bulbs have failed:
H1 Bulb Variant Output Lumens Life Hours
Standard (plain) 1550 lm 650 hr
Long Life 1460 lm 1200 hr
Plus+30
High Efficacy 1680 lm 400 hr
Plus+50
Ultra High Efficacy 1750 lm 350 hr
Blue glass
"Extra white" 1380 lm 250 hr
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" (spark blue, 8500K blue, etc.) type bulb sales and satisfy consumers desiring a different headlamp appearance with a legal and safe product. The retail-level marketers have an easy sell here; Pep Boys offers a "Silverstar 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 good 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. It has, on the other hand, been shown that these bulbs cause more glare than clear bulbs. Can you see better with this sort of bulb? No, probably not. Some people vigourously defend blue-glass bulbs, insisting they can see better. But that's another 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 probably doesn't help safety.
It should be mentioned that while these are critical questions that ought to be asked, they are academic to some degree if what you're deciding is whether to use a no-name bulb or the product of a reputable manufacturer, such as Narva, Candlepower, Osram, Philips, or GE.
OK, So These Extra-White Bulbs Aren't The Best Choice For Maximizing My Headlamps' Performance. What Should I Get Instead?
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 glass. Narva RangePower+50 and RangePower+30, GE Night Hawk, and Philips Vision Plus, and Osram Silver Star are the ones to get.
Wait a Minute, Earlier You Said Silver Star Bulbs Have Blue Glass!
It's a name game: Osram, the well-established German lampmaker, sells a line of automotive bulbs they call "Silver Star". These are Osram's top-of-the-range headlamp bulbs, equivalent to Narva RangePower+50, GE Night Hawk, Philips VisionPlus, and Tungsram Megalight Premium. They produce the maximum legal amount of light while staying within legal power consumption limits. They have colorless 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 "Silver Star", but it's not the same product. The Sylvania Silver Stars have blue glass. 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 overdriven to get a legal amount of light despite the blue glass.
To get the best possible seeing performance at night, don't choose extra-white bulbs.
What's the Scoop on "Extra White" Bulbs From Reputable Manufacturers?
You're asking about the current crop of bulbs, widely available in auto parts stores, with a blue absorption filter on the bulb glass, which is there to make the light look whiter. These bulbs are generally safe and legal, though not advantageous, to use in your car.
Some people feel that "whiter" light is better. Some people prefer the appearance of the headlamp when fitted with these bulbs. 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 pseudoscientific claims. Here's how this claim works: Higher-wattage bulbs of a given type generally appear whiter than lower-wattage bulbs. Think of the last 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 mimics the color of a higher wattage bulb, but not its performance. However, there's no getting something for nothing. The altered light color does not mean you're getting more light, or better quality light, just that the light is of a different color.
In fact, you get less usable 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.
But If That's True, Then How Come These Bulbs Have All The DOT and ECE Approval Markings Saying It's OK To Use Them On The Road?
The name-brand "extra white" bulbs mostly produce legal light output, true. But there's a lot of wiggle room in the bulb standards that permit two bulbs of the same format to put out significantly different amounts of 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 at 12.8v, plus or minus 15 percent. That means that in order to be legally certifiable as conforming to Federal standards, 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. On a dark road, I want 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? Most times, this information isn't available, for it's often made unavailable by bulb manufacturers. Some of the bulbs come with specification sheets giving a wattage and lumen rating, but these don't list actual output, they simply list the nominal specification contained in the Federal standard. The assumption they want you to make is that the bulb you're holding in your hand actually produces the nominal amount of light. In most cases, with blue glass, they don't. About all that can truthfully be said is that they're safe, they're legal, they're not dangerously poor performers like illegal blue bulbs are, but they do not give an actual performance improvement.
So If Blue Filtration Steals Light, How Do They Still Make These Bulbs Produce Legal Output With The Blue Filter?
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 reduce the output so it's 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 middleof the legal range. Here again, though, we can't have something for nothing.It took reputable 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. The cost? Bulb lifetime. The filament changes made to produce enough extra light that the bulb will still be legal despite the blue-filtration losses mean the filament's lifespan is shortened considerably.
Here's actual data for for output and lifespan at 13.2v for H1 bulbs. The numbers here are a composite of values applicable to the products of the three major manufacturers' bulbs. Each maker's product in each category is slightly different but not significantly so, and while the absolute numbers differ with different bulb types, the relative comparison patterns hold good for whatever bulb type you consider. Lifespan is given as Tc, the hour figure at which 63.2 percent of the bulbs have failed:
H1 Bulb Variant Output Lumens Life Hours
Standard (plain) 1550 lm 650 hr
Long Life 1460 lm 1200 hr
Plus+30
High Efficacy 1680 lm 400 hr
Plus+50
Ultra High Efficacy 1750 lm 350 hr
Blue glass
"Extra white" 1380 lm 250 hr
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" (spark blue, 8500K blue, etc.) type bulb sales and satisfy consumers desiring a different headlamp appearance with a legal and safe product. The retail-level marketers have an easy sell here; Pep Boys offers a "Silverstar 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 good 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. It has, on the other hand, been shown that these bulbs cause more glare than clear bulbs. Can you see better with this sort of bulb? No, probably not. Some people vigourously defend blue-glass bulbs, insisting they can see better. But that's another 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 probably doesn't help safety.
It should be mentioned that while these are critical questions that ought to be asked, they are academic to some degree if what you're deciding is whether to use a no-name bulb or the product of a reputable manufacturer, such as Narva, Candlepower, Osram, Philips, or GE.
OK, So These Extra-White Bulbs Aren't The Best Choice For Maximizing My Headlamps' Performance. What Should I Get Instead?
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 glass. Narva RangePower+50 and RangePower+30, GE Night Hawk, and Philips Vision Plus, and Osram Silver Star are the ones to get.
Wait a Minute, Earlier You Said Silver Star Bulbs Have Blue Glass!
It's a name game: Osram, the well-established German lampmaker, sells a line of automotive bulbs they call "Silver Star". These are Osram's top-of-the-range headlamp bulbs, equivalent to Narva RangePower+50, GE Night Hawk, Philips VisionPlus, and Tungsram Megalight Premium. They produce the maximum legal amount of light while staying within legal power consumption limits. They have colorless 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 "Silver Star", but it's not the same product. The Sylvania Silver Stars have blue glass. 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 overdriven to get a legal amount of light despite the blue glass.
To get the best possible seeing performance at night, don't choose extra-white bulbs.
12-04-2006, 11:48 AM
#23
AudiWorld Super User
PIAA??? The "55W = 85W" type claims are a sham....
Superwhites
Claims ("55w = 85w", etc.) made for "Superwhite" type bulbs are very misleading. They simply aren't true. Here's the full scoop!
CLAIM: "SuperWhite" bulbs produce 85W of light from 55W of electricity
REALITY: "Superwhite" ("Hyperwhite", "UltraWhite", "Platinum", etc., basically any bulb advertised as being "whiter" than normal) bulbs produce more glare and less seeing light than standard bulbs.
The "55W = 85W" type claims are a sham. Here's how these kinds of pretend wattage numbers are cooked-up: The blue or purple filtration coating on the glass tints the light so that it is "whiter". Most bulbs that actually produces more light (i.e., higher-wattage bulbs) also burn with a whiter color than standard-wattage bulbs. With these color-coated bulbs, only the light color, and not the actual light output, imitates a high-power bulb. There is no seeing advantage to "whiter" light, though some people seem to think that others will look upon headlamps so equipped and go "Wow, cool!". Why they believe anyone else cares what color their headlamps are is anybody's guess.
A major reason why many people find many US-specification headlamps in need of upgrading is because many such headlamps have very low levels of foreground light, which creates a "black hole" on the road in front of the car. There's often insufficient lateral light (left and right) to see critters or people before they run into the road. The "hot spot" creates a narrow tunnel of light that disappears "out there somewhere", with no visual cue to where the beam (and therefore the driver's seeing range or "preview") ends. But these headlamp performance aspects are governed by the optics of the lamp, not by the color of the light. Bulbs with blue or purple tinted glass never improve the performance of your headlamps. They may leave it relatively unchanged, or they may severely reduce it, but they never improve it.
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. This also addresses the related claims that
CLAIM: "I've got pictures that prove the brightness difference!"
REALITY: Photographs, film or digital, cannot accurately represent the intensity of a light or lamp, because of the many significant differences in the perception of light by the human eye vs. the camera. By simply adjusting the exposure settings or white balance, virtually any bulb or lamp can be "shown" to be superior to virtually any other.
BOTTOM LINE: The laws of physics are the laws of physics. They don't bend even for the highest-paid advertising agency. There is no way to get "85 watts of light for 55 watts of electricity." Tinted bulbs aren't better.
Claims ("55w = 85w", etc.) made for "Superwhite" type bulbs are very misleading. They simply aren't true. Here's the full scoop!
CLAIM: "SuperWhite" bulbs produce 85W of light from 55W of electricity
REALITY: "Superwhite" ("Hyperwhite", "UltraWhite", "Platinum", etc., basically any bulb advertised as being "whiter" than normal) bulbs produce more glare and less seeing light than standard bulbs.
The "55W = 85W" type claims are a sham. Here's how these kinds of pretend wattage numbers are cooked-up: The blue or purple filtration coating on the glass tints the light so that it is "whiter". Most bulbs that actually produces more light (i.e., higher-wattage bulbs) also burn with a whiter color than standard-wattage bulbs. With these color-coated bulbs, only the light color, and not the actual light output, imitates a high-power bulb. There is no seeing advantage to "whiter" light, though some people seem to think that others will look upon headlamps so equipped and go "Wow, cool!". Why they believe anyone else cares what color their headlamps are is anybody's guess.
A major reason why many people find many US-specification headlamps in need of upgrading is because many such headlamps have very low levels of foreground light, which creates a "black hole" on the road in front of the car. There's often insufficient lateral light (left and right) to see critters or people before they run into the road. The "hot spot" creates a narrow tunnel of light that disappears "out there somewhere", with no visual cue to where the beam (and therefore the driver's seeing range or "preview") ends. But these headlamp performance aspects are governed by the optics of the lamp, not by the color of the light. Bulbs with blue or purple tinted glass never improve the performance of your headlamps. They may leave it relatively unchanged, or they may severely reduce it, but they never improve it.
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. This also addresses the related claims that
CLAIM: "I've got pictures that prove the brightness difference!"
REALITY: Photographs, film or digital, cannot accurately represent the intensity of a light or lamp, because of the many significant differences in the perception of light by the human eye vs. the camera. By simply adjusting the exposure settings or white balance, virtually any bulb or lamp can be "shown" to be superior to virtually any other.
BOTTOM LINE: The laws of physics are the laws of physics. They don't bend even for the highest-paid advertising agency. There is no way to get "85 watts of light for 55 watts of electricity." Tinted bulbs aren't better.
12-04-2006, 11:49 AM
#24
AudiWorld Super User
Disadvantages of HID
Disadvantages of HID
There are physiological disadvantages to HID auto headlamps that do not exist with glowing-filament lamps.
Probably the biggest issue is HID headlamps' significantly worse color rendering index (CRI), which is in the high-60s to low-70s range. Halogen headlamps' CRI tends to be around 90 to 97 or so. In English, this means that the human eye's color perception and differentiation is much, much better under halogen light than under the light produced by automotive HID headlamps.
Now, how do we reconcile this with the ad copy that seems universally to talk about how HID headlamps' light is closer to daylight? Well, from a color temperature standpoint, that's generally true. However, that's not the whole story. Color temperature is only one factor that goes into describing the quality of light from such a thing as a headlamp. But here's the tricky part: There's no evidence that "closer to daylight" is the right stuff to drive with at night. Sure, an easy case can be made by just assuming that because daylight is what we have during the day, daylight is what we ought to have at night, too. But it isn't that simple at all. The eye has a very different set of jobs to do, using a different box of tools, at night compared to the job and tools during the day. The extent to which this influences your safety behind HID headlamps is not currently known. The full extent of the current knowledge on the topic as relates to current HID headlamps is "You can probably see colors well enough to be safe". But that's it! (Note that it's from the same researchers who say that you can see well enough to be safe when driving e.g. a '93-'97 Camaro with those miniature oblong sealed beams...) So all the hype about "closer to daylight" is really meaningless in the real world, and may in fact be misleading; there is research showing improved distance perception with headlight of *lower* color temperature, for any given intensity. Certainly any kind of shift towards the blue (as with HID headlamps) is a step in the wrong direction in inclement weather (fog, rain, snow, etc.).
As an illustration of the fact that color temperature does not automatically bear on headlamp quality, consider this: The selective-yellow headlamps required for so many decades in France were shown, in a couple of studies, to improve (or at least not to reduce) driver performance at night. There are some color issues with this light color (it's hard to tell a yellow road lane marking from a white one, for instance), these are easy to deal with by changing the lane marking color or using only one color. BUT, a sodium lamp, which is a kind of HID lamp, would make a *lousy* headlamp even though its color temperature is not far from that of a selective-yellow headlamp. That's because sodium lamps have EXTREMELY low color rendering indices. Many sodium lamps suck almost ALL of the color from whatever they illuminate, creating a black-and-yellow world. There are sodium safelights for use in photo darkrooms, and the monochromatic-world effect you perceive in such a darkroom is very eery until you get used to it. In a driving task, this would be a disaster! Color is a very important information carrier in our task to see what we're seeing.
Now, HID headlamps do have a big technical advantage over most current glowing-filament headlamps in that the efficiency of the light source (measured in a straightforward, easy-to-understand way: Lumens per Watt) is quite high. As a result, an arc capsule that consumes only 35 watts can produce double to triple the *amount* of light (around 3200 Lm) as can a typical halogen bulb (around 1500 Lm in the better designs, e.g. H7). So that's good, right? Well, it gives the designer of the headlamp a couple of options: He can keep the same performance, but have a much smaller headlamp, or he can keep the same size headlamp, and have the potential for higher performance. But now we hit another "it's not quite that simple".
A headlamp isn't a flood lamp. With a flood lamp, we put electricity in one end, and we get light out the other end, and we don't really care where the light is, as long as it's in a big ("flood") beam. A headlamp is a much more complex animal, 'cause it has a much harder job to do. It has to maximize your distance vision while minimizing glare to other drivers. It has to light up everything that you need to see, BUT not light up areas that would detract from your ability to see what you need to see. The first point makes it very difficult to improve low-beam headlamps, because increases in seeing distance almost always bring with them higher glare.
The second point is even more crucial. You remember from above my statement that the eye has a different job to do at night than during the day; here's where that comes into play.
During the day, pretty much everything is illuminated relatively evenly. If it's sunny out, everything's bright. If it's cloudy out, contrast is reduced and colors are muted. If it's foggy out, everything's fuzzy. But at night, your world consists not of "everything", but of that which is illuminated by your headlamps. Everything outside of that "world" is dark. Which is fine, except that your "world" moves with you! The extreme contrast between your "world" (that which is illuminated) and everything else (not illuminated) creates the difficulty. That's why we have headlamp glare at night, why we squint when we come out of a movie theatre after watching a perfectly bright screen for 3 hours, why we hold our hand in front of our eyes when looking in the direction of the sunset and trying to read a road sign. It happens on that big scale (inside/outside your "world") and it also happens *within* that "world".
If you illuminate the foreground very strongly, your eyes will adapt to that big area of strong illumination, your pupils will become smaller, and your distance vision will be reduced. (On the other hand, if you take the route prescribed for so long by US headlamp regulations and have very LITTLE foreground illumination, you'll have a "black hole" in front of the car, and you'll be straining to see what you're about to run over...)
So how does this relate to HID headlamps? Well, suddenly we have all this extra light to work with, because we're using an HID arc capsule instead of a bulb. Where are we going to put the extra light? We can put some of it into the high-intensity zone of the beam (the "hot spot") to improve distance vision, but we can't put too much of it there, 'cause we'll glare other drivers (and exceed regulated maximum intensities). We can spread some of it around in the rest of the beam, but there are often even stricter maxima outside of the hot spot or zone, and too much "generalized" light causes veiling glare and backdazzle in bad weather. So we put a lot of it in the foreground. To an extent, that's a good thing, because US headlamps have typically had too little foreground light (see above). But over a certain level, which is quite easy to exceed with an HID headlamp, undesireable things start to happen. We sacrifice distance vision, we get high levels of reflected-light glare on wet roads, that sort of thing.
But what about all the rave reviews you read in magazines and on Usenet about how marvelous HID headlamps are? Well, here's the double whammy of high levels of foreground light: When you can see every last pebble in the road, all the way across, it's very comforting. You don't have to strain to see what's immediately in front of the vehicle. And the most recent research seems to be suggesting that this, to an extent, improves driver performance at night, possibly because with the foreground adequately illuminated, we tend to trust our peripheral vision to handle the foreground, and keep focussed out in the distance where we should be looking. (See above comments regarding too-low levels of foreground light in many US headlamps...). BUT, foreground illumination is *only one* performance aspect of a headlamp, and it's very, very easy to judge a headlamp "good" because of very strong foreground light, when in fact the distance vision isn't so grand. In short (finally!) an HID headlamp has a strong tendency to create a false sense of security.
There's (even) more to it than all of this, but I think it's time to stop for now. HID headlamps can be an improvement over halogen ones, but it's not automatically the case, hype notwithstanding. Beam design is much more crucial than light source.
There are new, extremely efficient halogen bulbs coming on the market that offer increased intensity without CRI problems or excessive-light problems. The glowing filament is going to be around for a long time. It's also reasonable to expect that HID headlamps will also develop.
There are physiological disadvantages to HID auto headlamps that do not exist with glowing-filament lamps.
Probably the biggest issue is HID headlamps' significantly worse color rendering index (CRI), which is in the high-60s to low-70s range. Halogen headlamps' CRI tends to be around 90 to 97 or so. In English, this means that the human eye's color perception and differentiation is much, much better under halogen light than under the light produced by automotive HID headlamps.
Now, how do we reconcile this with the ad copy that seems universally to talk about how HID headlamps' light is closer to daylight? Well, from a color temperature standpoint, that's generally true. However, that's not the whole story. Color temperature is only one factor that goes into describing the quality of light from such a thing as a headlamp. But here's the tricky part: There's no evidence that "closer to daylight" is the right stuff to drive with at night. Sure, an easy case can be made by just assuming that because daylight is what we have during the day, daylight is what we ought to have at night, too. But it isn't that simple at all. The eye has a very different set of jobs to do, using a different box of tools, at night compared to the job and tools during the day. The extent to which this influences your safety behind HID headlamps is not currently known. The full extent of the current knowledge on the topic as relates to current HID headlamps is "You can probably see colors well enough to be safe". But that's it! (Note that it's from the same researchers who say that you can see well enough to be safe when driving e.g. a '93-'97 Camaro with those miniature oblong sealed beams...) So all the hype about "closer to daylight" is really meaningless in the real world, and may in fact be misleading; there is research showing improved distance perception with headlight of *lower* color temperature, for any given intensity. Certainly any kind of shift towards the blue (as with HID headlamps) is a step in the wrong direction in inclement weather (fog, rain, snow, etc.).
As an illustration of the fact that color temperature does not automatically bear on headlamp quality, consider this: The selective-yellow headlamps required for so many decades in France were shown, in a couple of studies, to improve (or at least not to reduce) driver performance at night. There are some color issues with this light color (it's hard to tell a yellow road lane marking from a white one, for instance), these are easy to deal with by changing the lane marking color or using only one color. BUT, a sodium lamp, which is a kind of HID lamp, would make a *lousy* headlamp even though its color temperature is not far from that of a selective-yellow headlamp. That's because sodium lamps have EXTREMELY low color rendering indices. Many sodium lamps suck almost ALL of the color from whatever they illuminate, creating a black-and-yellow world. There are sodium safelights for use in photo darkrooms, and the monochromatic-world effect you perceive in such a darkroom is very eery until you get used to it. In a driving task, this would be a disaster! Color is a very important information carrier in our task to see what we're seeing.
Now, HID headlamps do have a big technical advantage over most current glowing-filament headlamps in that the efficiency of the light source (measured in a straightforward, easy-to-understand way: Lumens per Watt) is quite high. As a result, an arc capsule that consumes only 35 watts can produce double to triple the *amount* of light (around 3200 Lm) as can a typical halogen bulb (around 1500 Lm in the better designs, e.g. H7). So that's good, right? Well, it gives the designer of the headlamp a couple of options: He can keep the same performance, but have a much smaller headlamp, or he can keep the same size headlamp, and have the potential for higher performance. But now we hit another "it's not quite that simple".
A headlamp isn't a flood lamp. With a flood lamp, we put electricity in one end, and we get light out the other end, and we don't really care where the light is, as long as it's in a big ("flood") beam. A headlamp is a much more complex animal, 'cause it has a much harder job to do. It has to maximize your distance vision while minimizing glare to other drivers. It has to light up everything that you need to see, BUT not light up areas that would detract from your ability to see what you need to see. The first point makes it very difficult to improve low-beam headlamps, because increases in seeing distance almost always bring with them higher glare.
The second point is even more crucial. You remember from above my statement that the eye has a different job to do at night than during the day; here's where that comes into play.
During the day, pretty much everything is illuminated relatively evenly. If it's sunny out, everything's bright. If it's cloudy out, contrast is reduced and colors are muted. If it's foggy out, everything's fuzzy. But at night, your world consists not of "everything", but of that which is illuminated by your headlamps. Everything outside of that "world" is dark. Which is fine, except that your "world" moves with you! The extreme contrast between your "world" (that which is illuminated) and everything else (not illuminated) creates the difficulty. That's why we have headlamp glare at night, why we squint when we come out of a movie theatre after watching a perfectly bright screen for 3 hours, why we hold our hand in front of our eyes when looking in the direction of the sunset and trying to read a road sign. It happens on that big scale (inside/outside your "world") and it also happens *within* that "world".
If you illuminate the foreground very strongly, your eyes will adapt to that big area of strong illumination, your pupils will become smaller, and your distance vision will be reduced. (On the other hand, if you take the route prescribed for so long by US headlamp regulations and have very LITTLE foreground illumination, you'll have a "black hole" in front of the car, and you'll be straining to see what you're about to run over...)
So how does this relate to HID headlamps? Well, suddenly we have all this extra light to work with, because we're using an HID arc capsule instead of a bulb. Where are we going to put the extra light? We can put some of it into the high-intensity zone of the beam (the "hot spot") to improve distance vision, but we can't put too much of it there, 'cause we'll glare other drivers (and exceed regulated maximum intensities). We can spread some of it around in the rest of the beam, but there are often even stricter maxima outside of the hot spot or zone, and too much "generalized" light causes veiling glare and backdazzle in bad weather. So we put a lot of it in the foreground. To an extent, that's a good thing, because US headlamps have typically had too little foreground light (see above). But over a certain level, which is quite easy to exceed with an HID headlamp, undesireable things start to happen. We sacrifice distance vision, we get high levels of reflected-light glare on wet roads, that sort of thing.
But what about all the rave reviews you read in magazines and on Usenet about how marvelous HID headlamps are? Well, here's the double whammy of high levels of foreground light: When you can see every last pebble in the road, all the way across, it's very comforting. You don't have to strain to see what's immediately in front of the vehicle. And the most recent research seems to be suggesting that this, to an extent, improves driver performance at night, possibly because with the foreground adequately illuminated, we tend to trust our peripheral vision to handle the foreground, and keep focussed out in the distance where we should be looking. (See above comments regarding too-low levels of foreground light in many US headlamps...). BUT, foreground illumination is *only one* performance aspect of a headlamp, and it's very, very easy to judge a headlamp "good" because of very strong foreground light, when in fact the distance vision isn't so grand. In short (finally!) an HID headlamp has a strong tendency to create a false sense of security.
There's (even) more to it than all of this, but I think it's time to stop for now. HID headlamps can be an improvement over halogen ones, but it's not automatically the case, hype notwithstanding. Beam design is much more crucial than light source.
There are new, extremely efficient halogen bulbs coming on the market that offer increased intensity without CRI problems or excessive-light problems. The glowing filament is going to be around for a long time. It's also reasonable to expect that HID headlamps will also develop.
12-04-2006, 11:50 AM
#25
AudiWorld Super User
Thinking of converting to HID?
Thinking of converting to HID?
So you've read about HID headlamps and have it in mind to convert your car. A few mouse clicks on the web, and you've found a couple of outfits offering to sell you a "conversion" that will fit any car with a given type of halogen bulb. STOP! Put away that credit card.
An HID kit consists of HID ballasts and bulbs for "retrofitting" into a halogen headlamp. Often, these products are advertised using the name of a reputable lighting company ("Real Philips kit! Real Osram kit! Real Hella kit!") to try to give the potential buyer the illusion of legitimacy. Fact: While some of the components in these kits are sometimes manufactured by the companies mentioned, the components aren't being put to their designed or intended use. Reputable companies like Philips, Osram, Hella, etc. NEVER endorse this kind of "retrofit" usage of their products.
Halogen headlamps and HID headlamps require very different optics to produce a safe and effective--not to mention legal--beam pattern. How come? Because of the very different characteristics of the two kinds of light source.
A halogen bulb has a cylindrical light source: the glowing filament. The space immediately surrounding the cylinder of light is completely dark, and so the sharpest contrast between bright and dark is along the edges of the cylinder of light. The ends of the filament cylinder fade from bright to dark. An HID bulb, on the other hand, has a crescent-shaped light source -- the arc. It's crescent-shaped because as it passes through the space between the two electrodes, its heat causes it to try to rise. The space immediately surrounding the crescent of light glows in layers...the closer to the crescent of light, the brighter the glow. The ends of the arc crescent are the brightest points, and immediately beyond these points is completely dark, so the sharpest contrast between bright and dark is at the ends of the crescent of light.
This diagram shows the very different characteristics of the filament vs. the arc:
When designing the optics (lens and/or reflector) for a lamp, the characteristics of the light source are *the* driving factor around which everything else must be engineered. If you go and change the light source, you've done the equivalent of putting on somebody else's eyeglasses: You can probably make them fit on your face OK, but you won't see properly.
Now, what about those "retrofit" jobs in which the beam cutoff still appears sharp? Don't be fooled; it's an error to judge a beam pattern solely by its cutoff. In many lamps, especially the projector types, the cutoff will remain the same regardless of what light source is behind it. Halogen bulb, HID capsule, cigarette lighter, firefly, hold it up to the sun--whatever. That's because of the way a projector lamp works. The cutoff is simply the projected image of a piece of metal running side-to-side behind the lens. Where the optics come in is in distributing the light under the cutoff. And, as with all other automotive lamps (and, in fact, all optical instruments), the optics are calculated based not just on where the light source is within the lamp (focal length) but also the specific photometric characteristics of the light source...which parts of it are brighter, which parts of it are darker, where the boundaries of the light source are, whether the boundaries are sharp or fuzzy, the shape of the light source, and so forth.
As if the optical mismatch weren't reason enough to drop the idea of "retrofitting" an HID bulb where a halogen one belongs--and it is reason enough!--there are even more reasons why not to do it. Here are some of them:
The only available arc capsules have a longitudinal arc (arc path runs front to back) on the axis of the bulb, but many popular halogen headlamp bulbs, such as 9004, 9007, H3 and H12, use a filament that is transverse (side-to-side) and/or offset (not on the axis of the bulb) central axis of the headlamp reflector). In this case, it is impossible even to roughly approximate the position and orientation of the filament with a "retrofit" HID capsule. Just because your headlamp might use an axial-filament bulb, though, doesn't mean you've jumped the hurdles--the laws of optical physics don't bend even for the cleverest marketing department, nor for the catchiest HID "retrofit" kit box.
The latest gimmick is HID arc capsules set in an electromagnetic base so that they shift up and down or back and forth. These are being marketed as "dual beam" kits that claim to address the loss of high beam with fixed-base "retrofits" in place of dual-filament halogen bulbs. (A cheaper variant of this is one that uses a fixed HID bulb with a halogen bulb strapped or glued to the side of it...yikes!) What you wind up with is two poorly-formed beams, at best. The reason the original equipment market has not adopted the movable-capsule designs they've been playing with since the mid 1990s is because it is impossible to control the arc position accurately so it winds up in the same position each and every time.
In the original-equipment field, there are single-capsule dual-beam systems appearing ("BiXenon", etc.), but these all rely on a movable optical shield, or movable reflector--the arc capsule stays in one place. The Original Equipment engineers have a great deal of money and resources at their disposal, and if a movable capsule were a practical way to do the job, they'd do it. The "retrofit" kits certainly don't address this problem anywhere near satisfaction. And even if they did, remember: Whether a fixed or moving-capsule "retrofit" is contemplated, solving the arc-position problem and calling it good is like going to a hospital with two broken ribs, a sprained ankle and a crushed toe and having the nurse say "Well, you're free to go home now, we've put your ankle in a sling!" Focal length (arc/filament positioning) is only just ONE issue out of several.
The most dangerous part of the attempt to "retrofit" Xenon headlamps is that sometimes you get a deceptive and illusory "improvement" in the performance of the headlamp. The performance of the headlamp is perceived to be "better" because of the much higher level of foreground lighting (on the road immediately in front of the car). However, the beam patterns produced by this kind of "conversion" virtually always give less distance light, and often an alarming lack of light where there's meant to be a relative maximum in light intensity. The result is the illusion that you can see better than you actually can, and that's not safe.
It's tricky to judge headlamp beam performance without a lot of knowledge, a lot of training and a lot of special equipment, because subjective perceptions are very misleading. Having a lot of strong light in the foreground, that is on the road close to the car and out to the sides, is very comforting and reliably produces a strong impression of "good headlights". The problem is that not only is foreground lighting of decidedly secondary importance when travelling much above 30 mph, but having a very strong pool of light close to the car causes your pupils to close down, worsening your distance vision...all the while giving you this false sense of security. This is to say nothing of the massive amounts of glare to other road users and backdazzle to you, the driver, that results from these "retrofits".
HID headlamps also require careful weatherproofing and electrical shielding because of the high voltages involved. These unsafe "retrofits" make it physically possible to insert an HID bulb where a halogen bulb belongs, but this practice is illegal and dangerous, regardless of claims by these marketers that their systems are "beam pattern corrected" or the fraudulent use of established brand names to try to trick you into thinking the product is legitimate. In order to work correctly and safely, HID headlamps must be designed from the start as HID headlamps.
What about the law, what does it have to say on the matter? In virtually every first-world country, HID "retrofits" into halogen headlamps are illegal. They're illegal clear across Europe and in all of the many countries that use European ECE headlight regulations. They're illegal in the US and Canada. Some people dismiss this because North American regulations, in particular, are written in such a manner as to reject a great many genuinely good headlamps. Nevertheless, on the particular count of HID "retrofits" into halogen headlamps, the world's regulators and engineers agree: DON'T!
The only safe and legitimate HID retrofit is one that replaces the entire headlamp--that is lens, reflector, bulb...the WHOLE shemozzle--with optics designed for HID usage. In the aftermarket, it is possible to get clever with the growing number of available products, such as Hella's modular projectors available in HID or halogen, and fabricate your own brackets and bezels, or to modify an original-equipment halogen headlamp housing to contain optical "guts" designed for HID usage. But just putting an HID bulb where a halogen one belongs is bad news all around.
So you've read about HID headlamps and have it in mind to convert your car. A few mouse clicks on the web, and you've found a couple of outfits offering to sell you a "conversion" that will fit any car with a given type of halogen bulb. STOP! Put away that credit card.
An HID kit consists of HID ballasts and bulbs for "retrofitting" into a halogen headlamp. Often, these products are advertised using the name of a reputable lighting company ("Real Philips kit! Real Osram kit! Real Hella kit!") to try to give the potential buyer the illusion of legitimacy. Fact: While some of the components in these kits are sometimes manufactured by the companies mentioned, the components aren't being put to their designed or intended use. Reputable companies like Philips, Osram, Hella, etc. NEVER endorse this kind of "retrofit" usage of their products.
Halogen headlamps and HID headlamps require very different optics to produce a safe and effective--not to mention legal--beam pattern. How come? Because of the very different characteristics of the two kinds of light source.
A halogen bulb has a cylindrical light source: the glowing filament. The space immediately surrounding the cylinder of light is completely dark, and so the sharpest contrast between bright and dark is along the edges of the cylinder of light. The ends of the filament cylinder fade from bright to dark. An HID bulb, on the other hand, has a crescent-shaped light source -- the arc. It's crescent-shaped because as it passes through the space between the two electrodes, its heat causes it to try to rise. The space immediately surrounding the crescent of light glows in layers...the closer to the crescent of light, the brighter the glow. The ends of the arc crescent are the brightest points, and immediately beyond these points is completely dark, so the sharpest contrast between bright and dark is at the ends of the crescent of light.
This diagram shows the very different characteristics of the filament vs. the arc:
When designing the optics (lens and/or reflector) for a lamp, the characteristics of the light source are *the* driving factor around which everything else must be engineered. If you go and change the light source, you've done the equivalent of putting on somebody else's eyeglasses: You can probably make them fit on your face OK, but you won't see properly.
Now, what about those "retrofit" jobs in which the beam cutoff still appears sharp? Don't be fooled; it's an error to judge a beam pattern solely by its cutoff. In many lamps, especially the projector types, the cutoff will remain the same regardless of what light source is behind it. Halogen bulb, HID capsule, cigarette lighter, firefly, hold it up to the sun--whatever. That's because of the way a projector lamp works. The cutoff is simply the projected image of a piece of metal running side-to-side behind the lens. Where the optics come in is in distributing the light under the cutoff. And, as with all other automotive lamps (and, in fact, all optical instruments), the optics are calculated based not just on where the light source is within the lamp (focal length) but also the specific photometric characteristics of the light source...which parts of it are brighter, which parts of it are darker, where the boundaries of the light source are, whether the boundaries are sharp or fuzzy, the shape of the light source, and so forth.
As if the optical mismatch weren't reason enough to drop the idea of "retrofitting" an HID bulb where a halogen one belongs--and it is reason enough!--there are even more reasons why not to do it. Here are some of them:
The only available arc capsules have a longitudinal arc (arc path runs front to back) on the axis of the bulb, but many popular halogen headlamp bulbs, such as 9004, 9007, H3 and H12, use a filament that is transverse (side-to-side) and/or offset (not on the axis of the bulb) central axis of the headlamp reflector). In this case, it is impossible even to roughly approximate the position and orientation of the filament with a "retrofit" HID capsule. Just because your headlamp might use an axial-filament bulb, though, doesn't mean you've jumped the hurdles--the laws of optical physics don't bend even for the cleverest marketing department, nor for the catchiest HID "retrofit" kit box.
The latest gimmick is HID arc capsules set in an electromagnetic base so that they shift up and down or back and forth. These are being marketed as "dual beam" kits that claim to address the loss of high beam with fixed-base "retrofits" in place of dual-filament halogen bulbs. (A cheaper variant of this is one that uses a fixed HID bulb with a halogen bulb strapped or glued to the side of it...yikes!) What you wind up with is two poorly-formed beams, at best. The reason the original equipment market has not adopted the movable-capsule designs they've been playing with since the mid 1990s is because it is impossible to control the arc position accurately so it winds up in the same position each and every time.
In the original-equipment field, there are single-capsule dual-beam systems appearing ("BiXenon", etc.), but these all rely on a movable optical shield, or movable reflector--the arc capsule stays in one place. The Original Equipment engineers have a great deal of money and resources at their disposal, and if a movable capsule were a practical way to do the job, they'd do it. The "retrofit" kits certainly don't address this problem anywhere near satisfaction. And even if they did, remember: Whether a fixed or moving-capsule "retrofit" is contemplated, solving the arc-position problem and calling it good is like going to a hospital with two broken ribs, a sprained ankle and a crushed toe and having the nurse say "Well, you're free to go home now, we've put your ankle in a sling!" Focal length (arc/filament positioning) is only just ONE issue out of several.
The most dangerous part of the attempt to "retrofit" Xenon headlamps is that sometimes you get a deceptive and illusory "improvement" in the performance of the headlamp. The performance of the headlamp is perceived to be "better" because of the much higher level of foreground lighting (on the road immediately in front of the car). However, the beam patterns produced by this kind of "conversion" virtually always give less distance light, and often an alarming lack of light where there's meant to be a relative maximum in light intensity. The result is the illusion that you can see better than you actually can, and that's not safe.
It's tricky to judge headlamp beam performance without a lot of knowledge, a lot of training and a lot of special equipment, because subjective perceptions are very misleading. Having a lot of strong light in the foreground, that is on the road close to the car and out to the sides, is very comforting and reliably produces a strong impression of "good headlights". The problem is that not only is foreground lighting of decidedly secondary importance when travelling much above 30 mph, but having a very strong pool of light close to the car causes your pupils to close down, worsening your distance vision...all the while giving you this false sense of security. This is to say nothing of the massive amounts of glare to other road users and backdazzle to you, the driver, that results from these "retrofits".
HID headlamps also require careful weatherproofing and electrical shielding because of the high voltages involved. These unsafe "retrofits" make it physically possible to insert an HID bulb where a halogen bulb belongs, but this practice is illegal and dangerous, regardless of claims by these marketers that their systems are "beam pattern corrected" or the fraudulent use of established brand names to try to trick you into thinking the product is legitimate. In order to work correctly and safely, HID headlamps must be designed from the start as HID headlamps.
What about the law, what does it have to say on the matter? In virtually every first-world country, HID "retrofits" into halogen headlamps are illegal. They're illegal clear across Europe and in all of the many countries that use European ECE headlight regulations. They're illegal in the US and Canada. Some people dismiss this because North American regulations, in particular, are written in such a manner as to reject a great many genuinely good headlamps. Nevertheless, on the particular count of HID "retrofits" into halogen headlamps, the world's regulators and engineers agree: DON'T!
The only safe and legitimate HID retrofit is one that replaces the entire headlamp--that is lens, reflector, bulb...the WHOLE shemozzle--with optics designed for HID usage. In the aftermarket, it is possible to get clever with the growing number of available products, such as Hella's modular projectors available in HID or halogen, and fabricate your own brackets and bezels, or to modify an original-equipment halogen headlamp housing to contain optical "guts" designed for HID usage. But just putting an HID bulb where a halogen one belongs is bad news all around.
12-04-2006, 12:01 PM
#26
AudiWorld Super User
Bulbs Type Chart
BULB TYPE WATTAGE LUMENS COMMENTS
9004/HB1 65/45 1200/700 SAE. Transverse filaments.
9004/HB1 +30 65/45 1230/720 High Efficiency
9005/HB3 65 1700 90 degree base ECE/SAE axial filament
9005/HB3 +30 55 1870 High Efficiency
9006/HB4 55 1000 90 degree base ECE/SAE axial filament
9006/HB4 +30 55 1095 High Efficiency
9005XS/HB3A 65 1700 Straight base 9005 ECE/SAE
9006XS/HB4A 55 1000 Straight base 9005 ECE/SAE
9007/HB5 65/55 1350/1000 SAE. Axial filaments.
9007/HB5 +30 65/55 1450/1095 High Efficiency
9011/HIR1 65 2350 SAE/ECE Halogen Infrared
9012/HIR2 55 1870 SAE/ECE Halogen Infrared
H1 55 1550 ECE/SAE axial filament. Headlamps, fog lamps, drive lamps...
H1 +30 55 1700 High Efficiency
H1 +50 55 1795 Ultra High Efficiency
H1 OVERWATT 100 2600 Not in plastic lamps!
H2 55 1800 ECE. Axial filament. Fog and drive lamps, some high beams. Very efficient (high lumens/watt)
H2 OVERWATT 100 2150 Not in plastic lamps!
H3 55 1450 ECE. Transverse filament. Fog and drive lamps.
H3 OVERWATT 100 2300 Not in plastic lamps!
R2 45/40 860/675 ECE non-halogen. Axial filaments, shielded lowbeam filamnent.
R2 Halogen 45/40 1030/740 Halogen version of R2
H4 60/55 1650/1000 ECE. Axial filaments, shielded lowbeam filamnent.
H4 +30 60/55 1700/1075 High Efficiency
H4 +50 60/55 1830/1148 Ultra High Efficiency
9003/HB2/H4 60/55 1650/1000 DOT-marked version of H4
H4 OVERWATT 100/90 2600/1620 Not in plastic lamps!
H4 OVERWATT 130/100 3550/2000 Not in plastic lamps!
H7 55 1500 ECE/SAE
H7 +50 55 1640 Ultra High Efficiency
H7 OVERWATT 65 2100 Race/special service only
H8 35 712 ECE/SAE. Primarily in fog lamps.
H9 65 2100 ECE/SAE. Very efficient.
H11 50 1200 ECE/SAE.
H13
(incorrectly called "9008" by Ford) 65/55 1700/1100 SAE/ECE Axial filaments.
D2S 35 3200 ECE/SAE AC arc-discharge (HID) projector lamps
D2R 35 2800 ECE/SAE AC arc-discharge (HID) reflector lamps
9500 xx xxxx ANSI DC arc-discharge(Sylvania Luminarc)
880 27 540 ANSI cosmetic toy "fog" straight base
881 27 540 ANSI cosmetic toy "fog" 90-deg base
884 27 540 ANSI cosmetic toy "drive" straight base
885 50 1255 ANSI cosmetic toy "drive" straight base
886 50 1255 ANSI cosmetic toy "drive" 90-deg base
889 27 540 ANSI cosmetic toy "drive" 90-deg base
893 37.5 940 ANSI cosmetic toy "fog" straight base
896 37.5 940 ANSI cosmetic toy "fog" 90-deg base
890 27 540 ANSI cosmetic toy "fog" straight base
892 16 350 ANSI cosmetic toy "fog" sick joke<ul><li><a href="http://www.danielsternlighting.com/tech/bulbs/bulb_types/bulb_types.html">Bulbs Type Chart</a></li></ul>
9004/HB1 65/45 1200/700 SAE. Transverse filaments.
9004/HB1 +30 65/45 1230/720 High Efficiency
9005/HB3 65 1700 90 degree base ECE/SAE axial filament
9005/HB3 +30 55 1870 High Efficiency
9006/HB4 55 1000 90 degree base ECE/SAE axial filament
9006/HB4 +30 55 1095 High Efficiency
9005XS/HB3A 65 1700 Straight base 9005 ECE/SAE
9006XS/HB4A 55 1000 Straight base 9005 ECE/SAE
9007/HB5 65/55 1350/1000 SAE. Axial filaments.
9007/HB5 +30 65/55 1450/1095 High Efficiency
9011/HIR1 65 2350 SAE/ECE Halogen Infrared
9012/HIR2 55 1870 SAE/ECE Halogen Infrared
H1 55 1550 ECE/SAE axial filament. Headlamps, fog lamps, drive lamps...
H1 +30 55 1700 High Efficiency
H1 +50 55 1795 Ultra High Efficiency
H1 OVERWATT 100 2600 Not in plastic lamps!
H2 55 1800 ECE. Axial filament. Fog and drive lamps, some high beams. Very efficient (high lumens/watt)
H2 OVERWATT 100 2150 Not in plastic lamps!
H3 55 1450 ECE. Transverse filament. Fog and drive lamps.
H3 OVERWATT 100 2300 Not in plastic lamps!
R2 45/40 860/675 ECE non-halogen. Axial filaments, shielded lowbeam filamnent.
R2 Halogen 45/40 1030/740 Halogen version of R2
H4 60/55 1650/1000 ECE. Axial filaments, shielded lowbeam filamnent.
H4 +30 60/55 1700/1075 High Efficiency
H4 +50 60/55 1830/1148 Ultra High Efficiency
9003/HB2/H4 60/55 1650/1000 DOT-marked version of H4
H4 OVERWATT 100/90 2600/1620 Not in plastic lamps!
H4 OVERWATT 130/100 3550/2000 Not in plastic lamps!
H7 55 1500 ECE/SAE
H7 +50 55 1640 Ultra High Efficiency
H7 OVERWATT 65 2100 Race/special service only
H8 35 712 ECE/SAE. Primarily in fog lamps.
H9 65 2100 ECE/SAE. Very efficient.
H11 50 1200 ECE/SAE.
H13
(incorrectly called "9008" by Ford) 65/55 1700/1100 SAE/ECE Axial filaments.
D2S 35 3200 ECE/SAE AC arc-discharge (HID) projector lamps
D2R 35 2800 ECE/SAE AC arc-discharge (HID) reflector lamps
9500 xx xxxx ANSI DC arc-discharge(Sylvania Luminarc)
880 27 540 ANSI cosmetic toy "fog" straight base
881 27 540 ANSI cosmetic toy "fog" 90-deg base
884 27 540 ANSI cosmetic toy "drive" straight base
885 50 1255 ANSI cosmetic toy "drive" straight base
886 50 1255 ANSI cosmetic toy "drive" 90-deg base
889 27 540 ANSI cosmetic toy "drive" 90-deg base
893 37.5 940 ANSI cosmetic toy "fog" straight base
896 37.5 940 ANSI cosmetic toy "fog" 90-deg base
890 27 540 ANSI cosmetic toy "fog" straight base
892 16 350 ANSI cosmetic toy "fog" sick joke<ul><li><a href="http://www.danielsternlighting.com/tech/bulbs/bulb_types/bulb_types.html">Bulbs Type Chart</a></li></ul>
Thread
Thread Starter
Forum
Replies
Last Post
PhoenixGTS
S4 / RS4 (B5 Platform) Discussion
28
07-30-2001 09:37 AM
