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Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / January 2006light color,auto vs photo lighting
maybe DS can answer this - - what's the problem w/ headlights being bluish, and they used to be yellowish,when studio lighting for photographers has been at fixed color temperatures for a long time? why can't headlights be made at fixed color temperatures like studio lighting? why this hassle of being a silly blue tint? Tom Seattle > maybe DS can answer this - - > what's the problem w/ headlights being bluish, and they used to be [quoted text clipped - 4 lines] > Tom > Seattle I'm not Daniel, but I would guess there's that silly little problem with efficiency. I'd suppose that being plugged into a wall outlet and having oodles of power to work with helps if you have a desired outcome with filters. Headlights have to (legally) run on 55/65W, and I believe the inherent output of a halogen-filled, tungsten filiment bulb is slightly yellow. Then there's HID, which DS has said could be of a similar color if they really wanted it to be. I've read that the the xenon gas in HIDs (to help with quicker startup) does tend to glow slightly blue though. Still - the color of current HID setups is supposed to be designed for "The Look" of something different than ordinary lighting. In a studio setting, I suppose the inefficiency of a filter can be overcome with a brighter light source. > I believe the inherent output of a halogen-filled, tungsten filiment > bulb is slightly yellow. No, if the lamp is run at its rated voltage, it's white. A continuous-line spectral power distribution with a Colour Rendering Index (CRI) in the high 90s. > Then there's HID, Also white, but a discontinous-line SPD with high spikes in the violet, blue and blue-green and a CRI in the mid 70s. > I've read that the the xenon gas in HIDs (to help with quicker startup) > does tend to glow slightly blue though. Yes, it does. You'll also notice that some HID car headlights appear much bluer than others. This is an optical effect, and there are entire websites devoted to photo essays on how to make your HID headlamps look bluer. > > I believe the inherent output of a halogen-filled, tungsten filiment > > bulb is slightly yellow. [quoted text clipped - 15 lines] > websites devoted to photo essays on how to make your HID headlamps look > bluer. Never mind that there are a couple of us here and there who think that your (generic "your" - not aimed at you, Dan. I know you already know better!) blue headlights would look coolest after being hammered, rocked, bashed, smashed, shot, or otherwise rendered permanently dark.  SignatureDon Bruder - dakidd@sonic.net - If your "From:" address isn't on my whitelist, or the subject of the message doesn't contain the exact text "PopperAndShadow" somewhere, any message sent to this address will go in the garbage without my ever knowing it arrived. Sorry... <http://www.sonic.net/~dakidd> for more info >>> I've read that the the xenon gas in HIDs (to help with quicker >>> startup) does tend to glow slightly blue though. [quoted text clipped - 7 lines] > your blue headlights would look coolest after being hammered, rocked, > bashed, smashed, shot, or otherwise rendered permanently dark. There are also automotive HID lamps ("bulbs") made by major makers, specifically designed and manufactured to filter out most of the blue. They certainly do that; the headlamp light when using one of these is selective yellow. Of course, if the maker of a particular lamp has twiddled the optics' geometry to produce a strong blue glint at the low beam cutoff, that cutoff will now appear green... > >>> I've read that the the xenon gas in HIDs (to help with quicker > >>> startup) does tend to glow slightly blue though. [quoted text clipped - 14 lines] > twiddled the optics' geometry to produce a strong blue glint at the low > beam cutoff, that cutoff will now appear green... Blue, green, orange with purple pinstripes... The color isn't the issue for me. What IS the issue is the friggin' wash of glare that *EVERY* "blue-headlights" vehicle I've ever faced puts out. SignatureDon Bruder - dakidd@sonic.net - If your "From:" address isn't on my whitelist, or the subject of the message doesn't contain the exact text "PopperAndShadow" somewhere, any message sent to this address will go in the garbage without my ever knowing it arrived. Sorry... <http://www.sonic.net/~dakidd> for more info >> I believe the inherent output of a halogen-filled, tungsten filiment >> bulb is slightly yellow. > > No, if the lamp is run at its rated voltage, it's white. A > continuous-line spectral power distribution with a Colour Rendering > Index (CRI) in the high 90s. The vast majority of halogen bulbs I've seen on the road seem to tend towards slightly yellow at most viewing angles. The Narva Rangepower +50 I got from you seem a little less so. Same for the 9006 GE Nighthawks I put in my folks' Camry. >> Then there's HID, > [quoted text clipped - 8 lines] > websites devoted to photo essays on how to make your HID headlamps look > bluer. Well - I live in a hilly area with many winding streets. I've seen real HIDs, and from certain angles, some have looked purple or blue and then look closer to white as I approach. The "HID-like" bulbs don't seem to have that effect. >> I believe the inherent output of a halogen-filled, tungsten filiment >> bulb is slightly yellow. > >No, if the lamp is run at its rated voltage, it's white. A continuous-line >spectral power distribution with a Colour Rendering Index (CRI) in the >high 90s. Tungsten lamps are defined by the definition of CRI to achieve 100. If the color temperature or correlated color temperature is in the mid or lower 3,000's, then the color would widely be seen as a yellowish or orangish "off-white". If the color temperature or correlated color temperature is in the 2,000's, then the color is even more orange-yellow or yellow-orange, although ideally an orange-yellowish white to whitish yelow-orange. Tungsten filament lamps are normally designed to have color temperature somewhere in the 2,000's to mid-3,000's Kelvin, usually at least mid-2,000's and usually at most not much above 3400. But by definition tungsten incandescent lamps have a color rendering index of 100, as well as daylight - even blue sky even when achieving a somewhat blue shade more of a whitish blue than bluish white, like 25,000 Kelvin. (Blue sky has been noted to sometimes achieve color close to that of infinity color temperature - which has CIE-1931 chromaticity coordinates of about x=.240 y=.234, a fairly whitish blue). Light reasonably achievable by tungsten lamps is defined to have a CRI of 100. So are reasonable shades of sunlight/daylight more blue (less orange-yellow) than usual achievable by tungsten-incandescent. - Don Klipstein (don@misty.com) >> No, if the lamp is run at its rated voltage, it's white. A >> continuous-line spectral power distribution with a Colour Rendering >> Index (CRI) in the high 90s. > > Tungsten lamps are defined by the definition of CRI to achieve 100. Of course they are. But I was including all the factors that go into the SPD of the light emitted from the headlamps of a typical vehicle in use, including the CMA quotient! ;-) > maybe DS can answer this - - > what's the problem w/ headlights being bluish, and they used to be [quoted text clipped - 4 lines] > Tom > Seattle Hi Tom, People have leapt into the technical side, but perhaps could have also answered your question more directly. In photography, the color temperature and balance required is defined by the film stock you use. I use Fujifilm 50ASA Velvia calibrated for Daylight for exterior photography and its sister film calibrated for Tungsten (3200K) for interiors and detail photography. As a result, when using the latter, I need to light my scene for 3200K if I want white surfaces to appear white when printed, or with daylight balance fluorescents for the former. Hence, the lamps are matched to the film, and there are only a few families of films. In vehicle headlights, the rendition of light is not nearly so important as its presence, quantity and distrbution - ie, it is helpful if the driver can see the road. As a result, there is limited value in selecting a particular color or quality of light. More important considerations in headlamp design are vibration resistance (essential), lamp life (useful), efficiency (important and increasingly so), initial cost (we care less than the car companies who want to save every cent they can), optical properties (essential for reflector design) and instant start (essential). Ask yourself, do all cars need to look the same? There is a feeling among car designers now that details like the color and quality of light are a part of the sales features of the car, as they are a significant part of the car's look. This is a newer consideration, and is driving a lot of what is being discussed by the other posters. I hope that helps, Thomas. > There is a feeling among car designers now that details like the color > and quality of light are a part of the sales features of the car, as > they are a significant part of the car's look. This is a newer > consideration, and is driving a lot of what is being discussed by the > other posters. And hence the move towards "HID look" halogen bulbs from even the more reputable manufacturers. It's amazing how many people are convinced by advertising that their "blue" headlights are somehow enhancing their safety because, "HIDs must be blue because blue light is safer". ** ** Half of the Sneetches have bellies with stars, and half of the Sneetches have no stars on thars. The problem is, all of the Sneetch Dads and Mothers want bellies that look like the ones of the others. But here comes that sly guy, Sylvester McBean, and his magical Star-On and Star-Off Machine, Who says "Step right in, I'm the Fix-it-Up Chappie. I'll change all your bellies and then you'll be happy!" -"The Sneetches and Other Stories" by Dr. Suess > > There is a feeling among car designers now that details like the color > > and quality of light are a part of the sales features of the car, as > > they are a significant part of the car's look. This is a newer > > consideration, and is driving a lot of what is being discussed by the > > other posters. Oh - found the DS post on the genesis of why HIDs tend towards blue. <http://groups.google.com/group/alt.autos.subaru/msg/8f3271925f9f7c33?dmode=source> "When the first automotive HID headlamp was demonstrated by a major European lighting manufacturer to automakers, in the early mid 1990s, it was a very well-designed optic, given the infant state of the art at the time. It handily outperformed most halogen lamps, and of course consumed less power. It was based on modified HPS (high-pressure Sodium) arc chemistry, and had a very similar operating appearance when warmed up to a halogen headlamp. The automakers reacted favourably to the increased performance and reduced power consumption, but rejected the lamp on the grounds that customers would be unwilling to pay any premium for a lamp that looked the same as the ordinary kind, regardless of increased performance." >> > There is a feeling among car designers now that details like the color >> > and quality of light are a part of the sales features of the car, as [quoted text clipped - 19 lines] >for a lamp that looked the same as the ordinary kind, regardless >of increased performance." This is certainly an interesting story, but is it true? I worked at GE Lighting during the time period they were developing HID auto headlamps and never heard of a headlamp based on HPS technology and never heard any discussion of wanting HID lamps to be "blue" to differentiate them from tungsten lamps. (Though similar issues were certainly discussed in relation to other products.) As far as I know, the feature that was supposed to make these lamps be worth more money was their higher output (for the fixed amount of power that was allowed to be used) which would in turn enable smaller headlamp reflectors and lower hood lines. Hence the higher amount of spill light. SignatureVic Roberts http://www.RobertsResearchInc.com To reply via e-mail: replace xxx with vdr in the Reply to: address or use e-mail address listed at the Web site. This information is provided for educational purposes only. It may not be used in any publication or posted on any Web site without written permission. >As far as I know, the feature that was supposed to make these lamps be worth more money was their higher output (for the fixed amount of power that was allowed to be used) which would in turn enable smaller headlamp reflectors and lower hood lines. Hence the higher amount of spill light. Manufcturers begged to be able to use oblong headlights back in the sixties, arguing that the lower profile, relative to the 7" round headlights proscribed by law, would lower hood lines and decrease wind resistance, increasing MPG. When legislators agreed, and permitted the low-profile oblongs, the stylists' response was to stack them one above the other. Incredible, but true. >>As far as I know, the feature that was supposed to make >these lamps be worth more money was their higher output (for [quoted text clipped - 8 lines] >low-profile oblongs, the stylists' response was to stack them one above >the other. Incredible, but true. Perhaps the world wasn't ready for low hood lines :-) SignatureVic Roberts http://www.RobertsResearchInc.com To reply via e-mail: replace xxx with vdr in the Reply to: address or use e-mail address listed at the Web site. This information is provided for educational purposes only. It may not be used in any publication or posted on any Web site without written permission. >This is certainly an interesting story, but is it true? I >worked at GE Lighting during the time period they were [quoted text clipped - 3 lines] >tungsten lamps. (Though similar issues were certainly >discussed in relation to other products.) That was the intent of the lamps on the 1993 Lincoln Mark VIII which was the first vehicle equipped with HID by a North American Auto Manufacturer. The higher output and lower hood line possibilities drove initial interest. There was early speculation that the "bluer" color might be better than the "yellow" color of the incandescents for driving, however it's not easy to measure and quantify "better for driving" since that is a highly subjective preference, and the argument still continues. Anyone who has driven a recent OEM HID headlight, will most likely rate it as better performing than any incandescent regardless of how you argue the science. > Anyone who has driven a recent OEM HID headlight, will most likely rate > it as better performing Well, sure! The human visual system is a lousy judge of its own performance. All it takes to generate highly favourable subjective ratings of headlamps is high levels of foreground light. >>The automakers reacted favourably to the increased performance >>and reduced power consumption, but rejected the lamp on the [quoted text clipped - 15 lines] > would in turn enable smaller headlamp reflectors and lower > hood lines. Hence the higher amount of spill light. The way I understood it was that the blue was a result of doping with Xenon, which was added only so that when the lamp was initially turned on there was sufficient light to drive with. An automotive HID lamp typically takes around 3 minutes to come up to full intensity. You can see this when first turning the lamp on the color is extremely blue quickly turning to blue-white. The biggest advantage of HIDs in the automotive world is power consumed - only 35W compared to 55W to halogen lower beams and 65W for halogen upper beams. And less power consumed means greater gas mileage and/or power drain for electric cars (I think all the electric or hybrid cars I've seen use HID lamps). Plus, you get the greater efficacy (more light for less power). And with today's designs, manufacturers are using the same 35W HID bulb for both lower and upper beams, using a moveable bulb shield to switch between the two functions. This leads to a smaller headlamp design since two cavities are merged into one, but not necessarily smaller reflectors which are extremely inefficient. SignatureDouglas Cummins Calcoast - ITL >>>The automakers reacted favourably to the increased performance >>>and reduced power consumption, but rejected the lamp on the [quoted text clipped - 22 lines] >see this when first turning the lamp on the color is extremely blue >quickly turning to blue-white. I must admit I have not seen a spectral curve of an HID headlamp, but I would be rather surprised if the xenon made any significant contribution to the spectrum when the lamp was fully warmed up. In normal metal halide lamps the mercury output is just about nil when the lamp is hot enough for the metal halides to be vaporized. The energy levels of xenon are higher than Hg so the xenon should have less contribution to the spectrum that the Hg in normal metal halide lamps. >The biggest advantage of HIDs in the automotive world is power consumed >- only 35W compared to 55W to halogen lower beams and 65W for halogen [quoted text clipped - 6 lines] >headlamp design since two cavities are merged into one, but not >necessarily smaller reflectors which are extremely inefficient. The moveable bulb shield is necessary for reasonable lamp life and performance irrespective of the size issues. If two separate arc tubes were used, or like the two filaments in an incandescent headlamp, or even separate high and low beam lamps, the arc tubes would have to be constantly switched on and off as the driver switched from high to low beam and back again. When GE was working on HID headlamps, some of the staff at Nela Park tried to convince me that people didn't change from high to low beams that often so this would not be a problem. These folks lived in a medium size city and drove either on well lit city streets of divided highways. Perhaps they never used their high beams. I live in a semi-rural area and drive on two-lane roads that have no street lights. On a typical 10 mile trip to the nearest mall, I may switch between high and low beams 10 to 20 times. SignatureVic Roberts http://www.RobertsResearchInc.com To reply via e-mail: replace xxx with vdr in the Reply to: address or use e-mail address listed at the Web site. This information is provided for educational purposes only. It may not be used in any publication or posted on any Web site without written permission. >>The way I understood it was that the blue was a result of doping with >>Xenon, which was added only so that when the lamp was initially turned [quoted text clipped - 12 lines] > contribution to the spectrum that the Hg in normal metal > halide lamps. But would you say that adding Xenon increases light output during the initial lamp warmup? The only other HID experience I have is with high output HID lighting like garage or stadium lighting where the light color has much less blue but the warmup time until full intensity is much longer than for automotive HID. I do watch the spectrum of HID headlamp bulbs as they start and warm up. It definitely changes over time until thermal stability sets. Whether it's because of the added Xenon or for another reason I can not say for certain, but that is what I had been told. >>The biggest advantage of HIDs in the automotive world is power consumed >>- only 35W compared to 55W to halogen lower beams and 65W for halogen [quoted text clipped - 14 lines] > and off as the driver switched from high to low beam and > back again. Unless the lower beam HID stays on all the time and a halogen lamp in a second cavity is used for upper beam, which is what the first generation of vehicles with HID lamps used, as well as a number of current models. As an aside, this is given as a "legitimate" reason for having blue-tinted halogen bulbs - to have a better color match to the HID lamps in use. Also, a separate HID upper beam wouldn't work well when on for short durations - a "flash-to-pass" would be ineffective since the startup intensity is lower than its warmed-up intensity. Another technology that was (or is still being) investigated is using a magnetic field to change the position of the arc-filament, much like a two-filament halogen headlamp bulb, so that the same bulb can be used to provide both lower and upper beam functions. Much more difficult, but it has the advantage of no moving parts to potentially fail. > When GE was working on HID headlamps, some of > the staff at Nela Park tried to convince me that people [quoted text clipped - 6 lines] > mall, I may switch between high and low beams 10 to 20 > times. But if you look at all vehicles as a whole, the majority of nighttime driving is with the lower beam. This is really only an argument against developing a separate HID upper beam, and possibly determining which is more economical - using a switchable bulb shield to create an upper beam from the lower beam cavity or having a second cavity with a halogen bulb for upper beam. SignatureDouglas Cummins Calcoast - ITL > But would you say that adding Xenon increases light output during the > initial lamp warmup? For sure. That's why it's there, as you originally said, to satisfy the technical and legal requirement for immediate light upon activation. > I do watch the spectrum of HID headlamp bulbs as they start and warm up. > It definitely changes over time until thermal stability sets. Whether > it's because of the added Xenon or for another reason I can not say for > certain, but that is what I had been told. The colour shift as they warm up is primarily due to the vapourisation of the halides in the arc chamber, with secondary effects from the yellow pool of molten halides in the bottom of the chamber. > Unless the lower beam HID stays on all the time and a halogen lamp in a > second cavity is used for upper beam, which is what the first generation > of vehicles with HID lamps used, as well as a number of current models. > As an aside, this is given as a "legitimate" reason for having > blue-tinted halogen bulbs - to have a better color match to the HID > lamps in use. Yep, this is cited as a reason, and I'd've put those same scarequotes around "legitimate". Chasin' a dragon that can't be caught. A halogen bulb filtered to create even a vaguely close colour match to HID tends to run afoul of minimum-flux, maximum-wattage and/or colourimetry requirements, as I'm sure you've seen in your own lab. A few carmakers (Lexus...) seem to have clued into the idea of using selective yellow fogs on models with HIDs to avoid the clashing appearance of two different whites being emitted from the front of the car. It solves the problem, and it even makes the HID headlamps look bluer, which of course is all the rage. Everyone's happy as long as the selective yellow light is made with Cadmium-free materials! > Also, a separate HID upper beam wouldn't work well when on for short > durations - a "flash-to-pass" would be ineffective since the startup > intensity is lower than its warmed-up intensity. True. Some vehicles in Europe have such a setup, though. > Another technology that was (or is still being) investigated is using a > magnetic field to change the position of the arc-filament, much like a > two-filament halogen headlamp bulb, so that the same bulb can be used to > provide both lower and upper beam functions. Much more difficult, but > it has the advantage of no moving parts to potentially fail. OSI was playing with this idea some years back. As far as I am aware, they gave up on it due to excessive difficulty reliably controlling the two positions of the arc over the service life of the bulb. DS >>>The way I understood it was that the blue was a result of doping with >>>Xenon, which was added only so that when the lamp was initially turned [quoted text clipped - 15 lines] >But would you say that adding Xenon increases light output during the >initial lamp warmup? Yes. That is why it is used. >The only other HID experience I have is with high >output HID lighting like garage or stadium lighting where the light [quoted text clipped - 40 lines] >provide both lower and upper beam functions. Much more difficult, but >it has the advantage of no moving parts to potentially fail. There have been a number of discussions about using magnetic fields to position the arc in the past. Perhaps even a patent. >> When GE was working on HID headlamps, some of >> the staff at Nela Park tried to convince me that people [quoted text clipped - 9 lines] >But if you look at all vehicles as a whole, the majority of nighttime >driving is with the lower beam. Not mine. I drive mostly on roads that do not have any street lights. I use my high beam all the time except when another car is approaching. I don't generalize my experience to the whole population and I don't think others should either. >This is really only an argument against >developing a separate HID upper beam, and possibly determining which is >more economical - using a switchable bulb shield to create an upper beam >from the lower beam cavity or having a second cavity with a halogen bulb >for upper beam. SignatureVic Roberts http://www.RobertsResearchInc.com To reply via e-mail: replace xxx with vdr in the Reply to: address or use e-mail address listed at the Web site. This information is provided for educational purposes only. It may not be used in any publication or posted on any Web site without written permission. > When GE was working on HID headlamps, some of the staff at Nela Park > tried to convince me that people didn't change from high to low beams [quoted text clipped - 4 lines] > mile trip to the nearest mall, I may switch between high and low beams > 10 to 20 times. Sure, but you and I are atypical. It's been found repeatedly that in North America at least, drivers tend not to use high beams even when the situation makes them the appropriate choice. (I might add that too many of them use high beams when they're situationally INappropriate...) >> When GE was working on HID headlamps, some of the staff at Nela Park >> tried to convince me that people didn't change from high to low beams [quoted text clipped - 9 lines] >situation makes them the appropriate choice. (I might add that too many of >them use high beams when they're situationally INappropriate...) I can agree that frequent high beam use my be atypical, but if only 30% or even 10% of drivers use their headlamps as I do and the HID headlamp system was designed to switch on and off as high beams were needed there will be a very large number of failed HID headlamps. SignatureVic Roberts http://www.RobertsResearchInc.com To reply via e-mail: replace xxx with vdr in the Reply to: address or use e-mail address listed at the Web site. This information is provided for educational purposes only. It may not be used in any publication or posted on any Web site without written permission. > (I might add that > too many of them use high beams when they're situationally > INappropriate...) Such as those IQ-challenged individuals who think it's appropriate to travel in heavy daytime highway traffic with every bulb in their front end blazing at maximum brightness...right into my rear view mirror. >> (I might add that too many of them use high beams when they're >> situationally INappropriate...) > > Such as those IQ-challenged individuals who think it's appropriate to > travel in heavy daytime highway traffic with every bulb in their front > end blazing at maximum brightness...right into my rear view mirror. In Canada we have that problem *AND* the opposite problem: People driving round at night with only their Daytime Running Lamps (or DRLs + parkers/tails). Grossly insufficient seeing for them, and in many cases greatly increased glare for other road users. Most of this problem would disappear immediately if CMVSS108 were changed to call for the instrument panel lights not to illuminate except with HEADLAMPS (not parkers alone). >>> (I might add that too many of them use high beams when they're >>> situationally INappropriate...) >> Such as those IQ-challenged individuals who think it's appropriate to >> travel in heavy daytime highway traffic with every bulb in their front >> end blazing at maximum brightness...right into my rear view mirror. >In Canada we have that problem *AND* the opposite problem: People >driving round at night with only their Daytime Running Lamps (or [quoted text clipped - 3 lines] >to call for the instrument panel lights not to illuminate except >with HEADLAMPS (not parkers alone). That would only be reasonable if it were headlamps OR front foglights. Signature/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia \ / ASCII ribbon campaign | "Laws do not persuade just because X against HTML mail | they threaten." / \ and postings | Lucius Annaeus Seneca, c. 4BC - 65AD. >> People driving round at night with only their Daytime Running Lamps (or >> DRLs + parkers/tails). Grossly insufficient seeing for them, and in >> many cases greatly increased glare for other road users. Most of this >> problem would disappear immediately if CMVSS108 were changed to call >> for the instrument panel lights not to illuminate except with HEADLAMPS >> (not parkers alone). > That would only be reasonable if it were headlamps OR front foglights. And *that*, in turn, would only be reasonable if front fog lamps were performance-regulated such that their use without headlamps, in applicable weather conditions, was safe. As it stands, many or most fog lamps available on North American-market vehicles are cosmetic toys, not useful lighting devices, therefore unsafe under any circumstances as the sole forward illumination devices. >>> People driving round at night with only their Daytime Running Lamps >>> (or DRLs + parkers/tails). Grossly insufficient seeing for them, and [quoted text clipped - 11 lines] > useful lighting devices, therefore unsafe under any circumstances as the > sole forward illumination devices. the factory fog lamps on my Trans Am throw out less light than the park lamps. I think I've turned them on twice... in the fog. But because my car (used to have) has DRL's and automatic headlights I don't (didn't) have a lot of control over them... [snip] > I must admit I have not seen a spectral curve of an HID > headlamp, but I would be rather surprised if the xenon made [quoted text clipped - 5 lines] > contribution to the spectrum that the Hg in normal metal > halide lamps. I have seen it, but I am not tellin :-)) Vic is right. After the lamps warm up, the Xenon does not make a significant contribution. It's one of the SD's for metal halides on my spectra page: http://ioannis.virtualcomposer2000.com/spectroscope/amici.html [snip]> > Vic Roberts SignatureIoannis --- http://ioannis.virtualcomposer2000.com/ > I must admit I have not seen a spectral curve of an HID headlamp Here's the newest burner (D4 Hg-free). It contains more blue than the now-standard D1/D2 lamps: http://www.nuconverter.de/assets/d4sbei35w.gif In <icnqs15b4r7fgon0n4kbob39fk8nbi8kil@4ax.com>, Vic Roberts wrote in part: >>The way I understood it was that the blue was a result of doping with >>Xenon, which was added only so that when the lamp was initially turned [quoted text clipped - 12 lines] >contribution to the spectrum that the Hg in normal metal >halide lamps. I have diffraction gratings and I have seen the spectra of metal halide lamps - automotive and otherwise. There mercury spectrum I usually (not always) find to be a least a little significant, although always a minority of the output (except sometimes not if the lamp is aged excessively or improperly operated.) The xenon in automotive ones has no contribution to the spectrum that I can see when the lamp is warmed up. - Don Klipstein (don@misty.com) In sci.engr.lighting Douglas G. Cummins <Douglas.Cummins@mapsoncalcoast-itl.com> wrote: >And less power consumed means greater gas mileage and/or power drain >for electric cars (I think all the electric or hybrid cars I've seen >use HID lamps). The Toyota Prius sold in the US from '01-'03 (four-door sedan body style) has plain old 9003 lamps. The '04 and up (four-door hatchback) have HID lamps. I _think_ all of the Insights and the early Accord hybrids had regular halogen lamps. Pure battery-electric cars often tend to be home-built, and HIDs are probably popular - every watt you don't put into the headlights gets you another 0.2" down the road. Matt Roberds > In sci.engr.lighting Douglas G. Cummins <Douglas.Cummins@mapsoncalcoast-itl.com> wrote: >> And less power consumed means greater gas mileage and/or power drain >> for electric cars (I think all the electric or hybrid cars I've seen [quoted text clipped - 3 lines] > style) has plain old 9003 lamps. The '04 and up (four-door hatchback) > have HID lamps. ...as optional equipment, with 9003 (H4) lights being standard. The HIDs aren't available on the Prius in Canada; they all have 9003s up here. > I _think_ all of the Insights and the early Accord hybrids had regular > halogen lamps. Correct, in North America. In sci.engr.lighting Daniel J. Stern <dastern@127.0.0.1> wrote: >> The Toyota Prius sold in the US from '01-'03 (four-door sedan body >> style) has plain old 9003 lamps. The '04 and up (four-door hatchback) >> have HID lamps. > >...as optional equipment, with 9003 (H4) lights being standard. I sit corrected. The HID lamps appear to be a popular option; most all of the '04-up Priuses I've seen recently seem to have them. >The HIDs aren't available on the Prius in Canada; they all have 9003s >up here. Is there any technical reason, like HID lamps not liking the cold, that this is so? Or is it some more mundane cost or styling reason. Matt Roberds >Is there any technical reason, like HID lamps not liking the cold, that >this is so? Or is it some more mundane cost or styling reason. HID lamps love cold weather :-) They run so hot that, unlike fluorescent lamps, their performance is not changed by normal ambient temperature changes. And, since automobile headlamps use xenon instead of Hg, they aren't even any harder to start when the temperature drops. (Due to the high pressure xenon they are hard to start all the time. ) SignatureVic Roberts http://www.RobertsResearchInc.com To reply via e-mail: replace xxx with vdr in the Reply to: address or use e-mail address listed at the Web site. This information is provided for educational purposes only. It may not be used in any publication or posted on any Web site without written permission. > HID lamps love cold weather :-) They run so hot that, unlike > fluorescent lamps, their performance is not changed by normal ambient > temperature changes. And, since automobile headlamps use xenon instead > of Hg Bzzzt! Current-production automobile HID headlamps most certainly *do* use Hg. Hg-free automotive HIDs (D3S, D3R, D4S, D4R) have just been approved recently. They are not interchangeable, optically or electrically, with the existing D1S, D1R, D2S, D2R bulbs. DS >> HID lamps love cold weather :-) They run so hot that, unlike >> fluorescent lamps, their performance is not changed by normal ambient [quoted text clipped - 6 lines] >the existing D1S, D1R, D2S, D2R bulbs. >DS You are correct. I should not have said "instead." I should have said "in addition to the Hg." Since they use a high pressure of xenon to provide "instant light" they are always hard to start, about as hard as a conventional metal halide lamp during hot restart. Hence the high voltage starting circuits of their ballasts. Normal HID lamps that do not have a fill of high pressure rare gas are relatively easy to start since both the Hg and the metal halides will condense when the lamp is "cold" and the arc tube pressure during starting will be controlled by the relatively low fill pressure of the rare gas used to enable starting. (As you know, this gas pressure is optimized for easy starting, not instant light.) SignatureVic Roberts http://www.RobertsResearchInc.com To reply via e-mail: replace xxx with vdr in the Reply to: address or use e-mail address listed at the Web site. This information is provided for educational purposes only. It may not be used in any publication or posted on any Web site without written permission. >> The HIDs aren't available on the Prius in Canada; they all have 9003s >> up here. > > Is there any technical reason, Yep! Canada requires Daytime Running Lamps. The least-expensive way of implementing them, both from a build-cost and warranty-costs standpoint, is to put the high beams in series with each other, but this is of course applicable only to incandescent lamps. It doesn't work with Xenon. Toyota apparently felt that the increased incidence of early HID component failure within vehicle warranty period, in addition to higher warranty replacement rates for parking, sidemarker and taillamp bulbs (required to be energized with full-intensity-lowbeam DRLs, and there is no other kind based on HID headlamps) would drive up warranty costs excessively. Apparently they also felt that using the turn signal DRL system they use on some of their trucks was for some reason a nonstarter. *shrug* So, all Canadian Prius buyers get 1972-tech headlamps. DS > The biggest advantage of HIDs in the automotive world is power consumed > - only 35W compared to 55W to halogen lower beams and 65W for halogen > upper beams. And less power consumed means greater gas mileage and/or > power drain for electric cars Surely a difference of 40W (20 on each side) is pretty negligable when compared with the power required for propulsion? Off the top of my head, I believe that the engine in my (small) car has a rated output of around 40kW. Personally I think that the major driving force behind HID headlamps is as a status symbol, with perhaps a secondary nod to the fact that it shouldn't be necessary to change the lamp within the lifetime of the car (am I right here? And will the ballasts need changing instead at much greater cost than a halogen lamp?) SignatureNice guys finish last. --------------------------------------------------------------- Simon Waldman, UK email: swaldman@firecloud.org.uk --------------------------------------------------------------- >> The biggest advantage of HIDs in the automotive world is power consumed >> - only 35W compared to 55W to halogen lower beams and 65W for halogen [quoted text clipped - 5 lines] >I believe that the engine in my (small) car has a rated output of around >40kW. If they designed HID to have the same light output as the tungsten halogen and then used equally efficient optics the power savings would be greater. >Personally I think that the major driving force behind HID headlamps is >as a status symbol, I agree. >with perhaps a secondary nod to the fact that it >shouldn't be necessary to change the lamp within the lifetime of the car >(am I right here? This advantage was discussed at GE during the HID headlamp development program. The fact that the lamps would be designed to last for the life of the car also eliminated the need to make them user-replaceable. Some at Nela Park claimed this would reduce the length of the whole car by at least 2" - which will it does is free up a few inches behind each headlamp :-) >And will the ballasts need changing instead at much >greater cost than a halogen lamp?) They shouldn't. Remember that the operating life of a car is very short compared to other electronic systems we use. If you have an average speed of 30 miles an hour and assume cars die after 100,000 miles (yes, I know many currently last longer) then the car has only operated for 3000 hours! If your average speed is greater the life in hours is less. If the mileage is greater then the life in hours is obviously longer. However, most cars that run for more than 100,000 miles were driven at average speed over 30 miles per hour, so the operating life is still less than 5000 hours in almost all cases. SignatureVic Roberts http://www.RobertsResearchInc.com To reply via e-mail: replace xxx with vdr in the Reply to: address or use e-mail address listed at the Web site. This information is provided for educational purposes only. It may not be used in any publication or posted on any Web site without written permission. >This advantage was discussed at GE during the HID headlamp >development program. The fact that the lamps would be [quoted text clipped - 3 lines] >least 2" - which will it does is free up a few inches behind >each headlamp :-) Hard to believe how badly I can garble things I type. The last sentence of the paragraph above should have read: Some at Nela Park claimed this would reduce the length of the whole car by at least 2" - while all it does is free up a few inches behind each head lamp. SignatureVic Roberts http://www.RobertsResearchInc.com To reply via e-mail: replace xxx with vdr in the Reply to: address or use e-mail address listed at the Web site. This information is provided for educational purposes only. It may not be used in any publication or posted on any Web site without written permission. > This is certainly an interesting story, but is it true? I worked at GE > Lighting during the time period they were developing HID auto headlamps > and never heard of a headlamp based on HPS technology Philips, I believe, was working on this. > and never heard any discussion of wanting HID lamps to be "blue" to > differentiate them from tungsten lamps That was from a Sylvania engineer who was working on what became the DC (Type 9500) HID system used not-briefly-enough in a couple of Lincoln models. >> There is a feeling among car designers now that details like the color >> and quality of light are a part of the sales features of the car, as [quoted text clipped - 15 lines] > The problem is, all of the Sneetch Dads and Mothers want bellies > that look like the ones of the others. Design continues to rule, sometimes to the point of trumping function, when it comes to headlighting as we have heard often on this ng. But the evidence continues to accumulate that "blue" headlamps, and especially the HID types, are more glaring for oncoming motorists than the white halogen types. The relative sensitivity and distribution of the rod and cone cells in the retina of the human eye are the reasons. So, this seems to be a situation where oncoming drivers are being penalized for style. Maybe that's not new, but enhancing one driver's safety at the expense of another's is still the wrong thing to do. Terry McGowan > But here comes that sly guy, Sylvester McBean, and his magical > Star-On and Star-Off Machine, [quoted text clipped - 3 lines] > > -"The Sneetches and Other Stories" by Dr. Suess > Design continues to rule, sometimes to the point of trumping function, > when it comes to headlighting as we have heard often on this ng. But [quoted text clipped - 6 lines] > penalized for style. Maybe that's not new, but enhancing one driver's > safety at the expense of another's is still the wrong thing to do. AMEN! DS > there is limited value in selecting a particular color or quality of > light. That's not necessarily so. The "color or quality" (SPD) of headlamp light affects the level of glare and backdazzle perceived by road users (the driver of the car with any given headlamps, and those other drivers who must view that same headlamp in operation). Too, there are potentially significant effects of SPD upon the effectiveness of the headlamp in disturbed environs (rain, fog, snow, dust...). > Ask yourself, do all cars need to look the same? Specious question, from where I sit. It has never been the case in North America that all cars look the same, even when all cars had just *one* kind of headlamp, the 7" round sealed beam. Even if we apply your question as I think you probably meant it (i.e., do all cars' headlamps have to produce the same kind of light), the answer is not as simple as yes or no. If there are significant glare and/or seeing effects of different SPDs, then styling/fashion/fad considerations must needs take a decided back seat. > There is a feeling among car designers now that details like the color > and quality of light are a part of the sales features of the car, as > they are a significant part of the car's look. ...and physiology and physics be damned. |
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