Automotive HID color questions
Steven Reiter
the actual light output, not whether it looks "cool" or not. And Daniel, I
know that you do not like the aftermarket conversions due to glare, etc.,
and I respect your view, anod would prefer to go with a unit that has the
proper focal length for proper focusing.
I am deciding which HID color to go with and need some help.
Which HID color has the greatest visible light output? Is it the 4100k, the
4300k, the 5000k, the 6000k, or the 7000k and up?
My limited experience with my piece of Fordtruck was that the 7000K had a
lot less light output than the 6000k ones. The 7000k lights were so poor as
to be considered unusable in my opinion. The 6000k ones are much better. Are
the 4100k lamps best? At what point do the lights' outout increase/decrease?
It looks to me that some people's 5000K lamps are tinted, whch cannot be
good in any way.
My understanding is that the closer to natural sunlight, the more sensitive
our eyes are to the light output.
Also has anyone had trouble with the quality of their HID kits? Are there
companies to definitely stay away from?
Thanks,
Steve
--
Steven Reiter
Lewisville, Texas
TKM
news:gPZR9.16551$9N5.1...@newsread2.prod.itd.earthlink.net...
Color temperature doesn't make much difference from the standpoint of
visibility for the motorist as far as I can tell from the research, but
higher color temperatures (more blue wavelengths) are more glaring to
pedestrians and oncoming motorist's eyes.
Terry McGowan
Daniel Stern Lighting
> I am researching HID retrofit kits for an Acura MDX.
The only acceptable retrofit is a complete headlamp originally designed
for an HID light source. Period. They are available for the MDX, as HID
headlamps became an option a couple years ago. So, either head to your
dealer or hit www.car-part.com (searchable used parts) and pick up the
assemblies.
> I am concerned about the actual light output, not whether it looks
> "cool" or not.
That's a good start.
> And Daniel, I know that you do not like the aftermarket conversions
> due to glare, etc., and I respect your view, anod would prefer to go
> with a unit that has the proper focal length for proper focusing.
It's nice to know you "respect my view", I suppose, but "proper focal
length for proper focusing" is not a "get out of jail free" card. It
doesn't change the fact that the optics of a headlamp are designed for ONE
light source. A halogen *OR* an arc discharge source. It doesn't matter
that the wrong light source is in the right place -- it's still wrong. The
MDX halogen headlamps produce extremely high levels of glare even with
just the normal halogen bulbs -- you propose to triple it.
> Which HID color has the greatest visible light output? Is it the 4100k, the
> 4300k, the 5000k, the 6000k, or the 7000k and up?
And if you're even looking at a site that offers these higher color
temperature options, you're already doomed.
> the 4100k lamps best?
Yes. The untampered, untinted, unscrewed-up HID burner produces 4100k
(nominal). Modifications from this give much less light. Example: Philips
and Osram both sell a 6000K burner. Its output is nearly 1000 lumens less
than that of their 4100K burner.
> My understanding is that the closer to natural sunlight, the more sensitive
> our eyes are to the light output.
Let's disabuse ourselves of false notions created by marketing hype: HID
headlamp light in NO way resembles natural sunlight.
> Also has anyone had trouble with the quality of their HID kits? Are there
> companies to definitely stay away from?
All of them.
There are many unsafe, illegal and noncompliant products on the market,
mainly consisting of an HID ballast and bulb for "retrofitting" into a
halogen headlamp. Halogen headlamps and HID headlamps require very
different optics to produce a safe and effective -- not to mention legal
-- beam pattern. It is not some great feat of upgrade engineering to put
an HID capsule where a halogen bulb belongs, it is just plain foolishness.
Some types of halogen headlamp bulbs (9004, 9007, H3) use a transverse
(side-to-side) and/or offset (not directly in line with the central axis
of the headlamp reflector) filament, the position and orientation of which
is physically impossible to match with a "retrofit" HID capsule. Even
those halogen headlamps that use axial-filament (9005, 9006, H1, H7) bulbs
are not safely or legitimately "convertible", regardless of what kinds of
"clever" products the junk vendors come up with.
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, examining isoscans of
the beam patterns produced by this kind of "conversion" reveals *less*
distance light, and often an alarming relative minimum where there's meant
to be a relative maximum in light intensity. When you *think* you can see
better than you can, you're *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.
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. It IS possible to get clever with
available products, such as Hella's modular projectors available in HID or
halogen, and fabricate your own brackets and bezels. But just putting an
HID bulb where a halogen one belongs is bad news all around.
> Steven Reiter
> Lewisville, Texas
Be advised that Texas has adopted Federal Motor Vehicle Safety Standard
108 into the state vehicle code, and the cops are enforcing it (good for
them!). HID "retrofit kits" render any headlamp noncompliant with 108,
therefore noncompliant with state law.
DS
Steven Reiter
Actually, the MDX is not nor has ever been available with HID lighting as a
factory option.
I am going to install HIDs; I am seeking the best matched lamps for the
vehicle.
Steve
--
Steven Reiter
Lewisville, Texas
"Daniel Stern Lighting" <das...@vrx.headlamp.net> wrote in message
news:Pine.SOL.4.33.030105...@alumni.engin.umich.edu...
Daniel Stern Lighting
> Daniel,
>
> Actually, the MDX is not nor has ever been available with HID lighting as a
> factory option.
Right, I was thinking of the RSX.
> I am going to install HIDs; I am seeking the best matched lamps for the
> vehicle.
There is none. You are bound and determined to do something wrong. I'm
sure you'll find no shortage of people happy to take your money in
exchange for what they assure you is a "beam pattern corrected" kit, and
I'm equally sure you'll take a look at the results, which I'd lay money
you're thoroughly unequipped and unqualified to judge, and declare them a
tremendous success because you have a snotload of purplish-white light
coming out the front of your SUV. You won't be any safer, and you'll be
endangering every other road user you encounter, but the hell with them --
right?
DS
Steven Reiter
perfect world, the factory lamps would provide proper illumination and come
with HID from the factory. Unfortunately, this is not a perfect world.
I am currently running HIDs in my daily driver, a piece of Ford F250. I am
using the APC aftermarket headlamps, which have a much better output than
the stock crap Ford installs and calls headlights. I was merely seeing if
you had a real world solution for the MDX. I guess not.
The HIDs in my F250 are a quantum leap over the factory lighting in any and
all circumstances, despite yor claims otherwise. Now I can see where I am
going at night.
If I need my high beams, I kick on my aircraft landing lights (3 250 watt GE
#4522 sealed beams in KC housings!)
I find that with the HIDs, I rarely need my high beams anymore.
Anyways, thanks for nothing, Daniel.
Steve
--
Steven Reiter
Lewisville, Texas
"Daniel Stern Lighting" <das...@vrx.headlamp.net> wrote in message
news:Pine.SOL.4.33.030105...@alumni.engin.umich.edu...
Justin Wolcott
HID replacement kits that are 100% legal
Greg R. Broderick
>> Daniel,
>>
>> Actually, the MDX is not nor has ever been available with HID
>> lighting as a factory option.
>
> Right, I was thinking of the RSX.
Actually, Daniel, the RSX (at least my 2003 model) wasn't / isn't
available with HID lighting as a factory option either. The RSX does
have available a dealer-installable foglight option.
If a HID lighting option had been available, I'd have gotten it on my
car. Since the HID lighting option wasn't available, I'm not going to
monkey with the (quite adequate, IMO) halogen lighting that the car came
equipped with (thanks in part to the advice on your web pages).
Best Regards
--
---------------------------------------------------------------------
Greg R. Broderick [rot13] te...@oynpxubyvb.qlaqaf.bet
[rot13] tnal...@fcrnxrnfl.arg
A. Top posters.
Q. What is the most annoying thing on Usenet?
---------------------------------------------------------------------
Stephen H. Westin
> In a perfect word, there would not be a need for upgraded headlamps. In a
> perfect world, the factory lamps would provide proper illumination and come
> with HID from the factory.
You realize, don't you, that those are two basically independent
statements? It's perfectly possible to provide "proper illumination"
with halogen lamps, nor does HID technology guarantee it.
Why not get ECE-code (European) lights for your truck? If it is sold
in Europe, such lamps exist, and offer both better beam control and
better illumination.
<snip>
--
-Stephen H. Westin
Any information or opinions in this message are mine: they do not
represent the position of Cornell University or any of its sponsors.
Brandon Sommerville
<superdu...@earthlink.net> wrote:
>In a perfect word, there would not be a need for upgraded headlamps. In a
>perfect world, the factory lamps would provide proper illumination and come
>with HID from the factory. Unfortunately, this is not a perfect world.
>
>I am currently running HIDs in my daily driver, a piece of Ford F250. I am
>using the APC aftermarket headlamps, which have a much better output than
>the stock crap Ford installs and calls headlights. I was merely seeing if
>you had a real world solution for the MDX. I guess not.
>
>
>The HIDs in my F250 are a quantum leap over the factory lighting in any and
>all circumstances, despite yor claims otherwise. Now I can see where I am
>going at night.
>
>If I need my high beams, I kick on my aircraft landing lights (3 250 watt GE
>#4522 sealed beams in KC housings!)
>
>I find that with the HIDs, I rarely need my high beams anymore.
>
>Anyways, thanks for nothing, Daniel.
There is no safe HID upgrade for your vehicle if you're just getting
"HID bulbs". Anything you do might *look* better but perform worse,
never mind causing significant glare for other drivers due to the
headlamp design differences.
Have you looked into E-code halogen lamps?
--
Brandon Sommerville
remove ".gov" to e-mail
The easy way is always mined.
Ricardo
(Stephen H. Westin) wrote:
>Why not get ECE-code (European) lights for your truck? If it is sold
>in Europe, such lamps exist, and offer both better beam control and
>better illumination.
And if that's not possible, good aux driving lamps can work wonders.
Even my el cheapo ones are better than nothing imho (well they do
have SAE-Y-86 on 'em, that's a start).
--
ricardo, ex-euroslav
vancouver bc canada
e-mail: sovietjamaicanguy <at> yahoo <dot> ca
for liability purposes: I *always* obey the law.
Douglas G. Cummins
HID option was only available in Europe, so technically one is available
although perhaps a little difficult for those in the 'States to get.
Douglas Cummins
Calcoast - ITL
Stephen H. Westin
> On 06 Jan 2003 12:46:06 -0500, westin*nos...@graphics.cornell.edu
> (Stephen H. Westin) wrote:
>
> >Why not get ECE-code (European) lights for your truck? If it is sold
> >in Europe, such lamps exist, and offer both better beam control and
> >better illumination.
>
> And if that's not possible, good aux driving lamps can work wonders.
> Even my el cheapo ones are better than nothing imho (well they do
> have SAE-Y-86 on 'em, that's a start).
Wonders for whom? We were talking about improving what you see without
blinding others. I really doubt that "el cheapo" lamps will do
both. The great thing about ECE lamps is that the low beam is *much*
better to see by, while arguably causing less glare to oncoming
drivers under most circumstances.
Ricardo
(Stephen H. Westin) wrote:
>> And if that's not possible, good aux driving lamps can work wonders.
>> Even my el cheapo ones are better than nothing imho (well they do
>> have SAE-Y-86 on 'em, that's a start).
>
>Wonders for whom?
For those of us lumbered with 9006/9005 flip beam DoT tiki lights
who want to be able to see at night when it's viable to engage the
high beam.
>We were talking about improving what you see without
>blinding others. I really doubt that "el cheapo" lamps will do
>both. The great thing about ECE lamps is that the low beam is *much*
>better to see by, while arguably causing less glare to oncoming
>drivers under most circumstances.
Completely agreed. But there's still a bittuva prisoner's dilemma in
so far as having ECE lights does not prevent others from dazzling
you with their 900x DoT tikis.
Arif Khokar
> In a perfect word, there would not be a need for upgraded headlamps.
If headlamp beam pattern standards in the US were more like ECE
standards, then we would be that much closer to a "perfect world"
> In a
> perfect world, the factory lamps would provide proper illumination and come
> with HID from the factory.
Mine did come HID from the factory and compared to the ECE spec
assemblies I have now, the light output and distribution from the
factory HIDs was crap.
> Unfortunately, this is not a perfect world.
True, but you don't have to make it worse by equipping your vehicle
with noncompliant lighting accessories.
> I find that with the HIDs, I rarely need my high beams anymore.
No low beam pattern provides sufficient light to drive at speeds above
30 to 35 mph without out driving the lighted area. Use your highbeams
when driving at faster speeds when traffic permits.
Pete Fagerlin
| No low beam pattern provides sufficient light to drive at speeds above
| 30 to 35 mph without out driving the lighted area.
Not true.
It really depends upon the lighting system and the braking ability of the
vehicle.
TKM
AC/DCdude17 <Je...@prontoREMOVETHISmail.com> wrote in message
news:3E1A48B3...@prontoREMOVETHISmail.com...
> X-No-Archive: Yes
>
> Daniel Stern Lighting wrote:
>
> >
> >
> > Yes. The untampered, untinted, unscrewed-up HID burner produces 4100k
> > (nominal). Modifications from this give much less light. Example:
Philips
> > and Osram both sell a 6000K burner. Its output is nearly 1000 lumens
less
> > than that of their 4100K burner.
> >
>
>
> In standard practice, light output is measured in lumens weighed to
photopic
> vision. Our scotopic vision(low illumination) has a increased sensitivity
to
> shorter wavelength. Some research shows that higher color temp light
source used
> to provide "low" level of illumination provides greater illumination
relative to
> lower color temp source with same photopic lumens as suggested in this
article.
>
>
http://www.electrolink.co.nz/CC256A1C0073A9F5/DCB530D95C0C8EBFCC2569280012C8
A6/F0F4FF9DEBDDA1F5CC256A1C0082CF32!Open
>
> ^one long line.
>
> So, after including our eye's different spectral sensitivity peak at
different
> light level, a higher color temp source with lower photopic lumens may
provide
> equal or greater illumination than a lower color temp source with higher
photopic
> vision weighed lumens.
>
> I have nothing to prove or disprove this, but it's something to take into
> consideration.
Not yet! There's no agreement on how it should be done. Even if there
were an agreed-upon system of photometry and even if there were some
agreed-upon recommendations for applying the information to practical
lighting situations, there's a missing link. In a driving situation you
don't know the adaptation level of the eye at any given time. Has a car
with glaring headlights just passed? Are you driving in an urban zone with
a high level of fixed lighting? What are you (the driver ) looking at? If
it's a foveal task (like reading a sign), you're only using cones and that
means you're using photopic vision.
It's interesting research and it's fun to think about how lighting practice
might be changed if it were taken into account; but at the moment there's no
way to do it.
Terry McGowan
Ricardo
<pe...@petefagerlin.com> wrote:
>| No low beam pattern provides sufficient light to drive at speeds above
>| 30 to 35 mph without out driving the lighted area.
>
>Not true.
>
>It really depends upon the lighting system and the braking ability of the
>vehicle.
Not to mention ambient light!
Daniel Stern Lighting
> "Steven Reiter" <superdu...@earthlink.net> wrote:
>
> > In a perfect word, there would not be a need for upgraded headlamps.
>
> If headlamp beam pattern standards in the US were more like ECE
> standards, then we would be that much closer to a "perfect world"
I think if we had one worldwide standard that basically amounted to the
bottom areas of BOTH standards' seeing-light zones were chopped off so
that the minimum acceptable performance were higher, the top area of the
US standard's glare zone were chopped off so that the maximum acceptable
glare were lower, and the top area of the ECE standard's upward stray
light standard were chopped off so that the maximum acceptable backdazzle
were lower, we'd be pretty much there.
> > Unfortunately, this is not a perfect world.
>
> True, but you don't have to make it worse by equipping your vehicle
> with noncompliant lighting accessories.
The original poster has a hard-on for HID. It doesn't seem to matter to
him that what he's doing will not give him lighting that is, in any real
sense, "better" than what he has. It also seems not to concern him in the
slightest that he'll be endangering every other road user he encounters.
Why on earth should he give a toss about such silly things as compliance?
> > I find that with the HIDs, I rarely need my high beams anymore.
>
> No low beam pattern provides sufficient light to drive at speeds above
> 30 to 35 mph without out driving the lighted area.
While the original poster's statement about HID low beams obviating the
need for high beams is straight out of the HID kit hawkers' bag of hyped
up nonsense, your "30-35mph" is overstating the case rather severely.
Seeing range with any given set of headlamps at a given height can easily
be determined using nothing more than simple geometry; vehicle
handling/braking info can then be plugged into this to determine maximum
safe speed under low beam illumination. The thing to remember -- and what
you're tangentially getting at here -- is that the limiting factor in
low-beam illumination range is geometric, not luminous.
DS
Daniel Stern Lighting
> In standard practice, light output is measured in lumens weighed to
> photopic vision. Our scotopic vision(low illumination) has a
> increased sensitivity to shorter wavelength.
<etc.>
Yes, but:
1) This research is very new and not robustly corroborated. It may become
so with further research, or it may not.
2) It's been demonstrated many, many times that the mesopic condition is a
wily and sly beast, often behaving contrary to how we suppose it "should"
or "must".
3) It's also been demonstrated robustly that effects upon seeing in
general, such as the one you mention, often exert no effect, an
insignificant effect or even an opposite effect upon perception *in the
context of the driving task* (e.g. color-related studies done at RPI's
Lighting Research Center).
For these three reasons and more, it is not possible to make
valid assumptions about driver performance under various types of
light by extrapolation from physiological and luminous qualities
alone, nor is it even remotely possible to parlay "kinda, sorta, maybe"
research results into anything contextually meaningful.
> I have nothing to prove or disprove this, but it's something to take into
> consideration.
No, it doesn't yet rise to the level of being worthy of consideration
vis-a-vis the originally-posted question. Maybe someday, but not yet.
> > Let's disabuse ourselves of false notions created by marketing hype: HID
> > headlamp light in NO way resembles natural sunlight.
> Daniel's correct. The quality of light from automotive HID is usually
> no better than gas station lights. Automotive HIDs are metal halide
> just as gas station lights are. You wouldn't consider gas station
> lights "natural" would you? It might give you a better white balance
> due to it's color temp that is closer to that of natural light than
> incandescent, but color rendition is horrendous.
> Philips D2S is rated at CRI 65
> Regular halogen has a CRI of 100.
Which is why we have the heavy (and thoroughly irrelevant) hammering on
"color temperature" as a pretend-factor in automotive lighting. "Look,
this nifty blue bulb has a color temperature of 8900! That's WAY higher
than 3150! Higher is better!" Never mind that only about 3 out of the
original 1000 lumens even makes it through the colored glass...
DS
Stephen H. Westin
> On 06 Jan 2003 18:06:37 -0500, westin*nos...@graphics.cornell.edu
> (Stephen H. Westin) wrote:
>
> >> And if that's not possible, good aux driving lamps can work wonders.
> >> Even my el cheapo ones are better than nothing imho (well they do
> >> have SAE-Y-86 on 'em, that's a start).
> >
> >Wonders for whom?
>
> For those of us lumbered with 9006/9005 flip beam DoT tiki lights
> who want to be able to see at night when it's viable to engage the
> high beam.
>
> >We were talking about improving what you see without
> >blinding others. I really doubt that "el cheapo" lamps will do
> >both. The great thing about ECE lamps is that the low beam is *much*
> >better to see by, while arguably causing less glare to oncoming
> >drivers under most circumstances.
>
> Completely agreed. But there's still a bittuva prisoner's dilemma in
> so far as having ECE lights does not prevent others from dazzling
> you with their 900x DoT tikis.
Right. But you can keep from making the problem worse.
TKM
Daniel Stern Lighting <das...@vrx.headlamp.net> wrote in message
news:Pine.SOL.4.33.03010...@alumni.engin.umich.edu...
And then there's the "cult" of folks promoting neodymium headlamps. Color
is easy to see and therefore easy to sell; but in the great lighting
scheme-of-things its role is still more involved with the art of lighting
rather than the science of seeing.
Terry McGowan
Daniel Stern Lighting
> And then there's the "cult" of folks promoting neodymium headlamps.
Ah yes. DK's one-man cult of True Belief in the power of Neodymium Oxide
to solve glare, increase low-beam visibility range to at least five miles,
eliminate those hazardous electrical fields he can "feel" coming from HID
headlamps, get rid of those pesky spots on your fine china, fight waxy
buildup on your no-wax floors, increase your gas mileage, make your coffee
taste better and help you stop smoking cigarettes.
It is a bafflement to me why editors and moderators continue to grant
audience (or editorial space) to that crackpot.
> Color is easy to see and therefore easy to sell; but in the great
> lighting scheme-of-things its role is still more involved with the art
> of lighting rather than the science of seeing.
Indeed. That said, I am interested to see what corroboration, if any,
develops for RPI LRC's study suggesting yellow light (white minus blue)
may facilitate certain aspects of visual perception related to the driving
task in a disturbed environment (rain, fog, snow). The interest is not
just practical (it would tend to explain the otherwise-inexplicably
persistent preference for yellow fog lamps in the face of regulatory and
manufacturing preference for white) but historical (it would tend to
vindicate the French...does anyone want to do that??) 8^{)}
DS
Martin Brown
Daniel Stern Lighting wrote:
Having driven in various countries I have to admit that the French yellow
filtered headlights are distinctly less painful at night if you are facing
into a stream of oncoming traffic. The odd blue HID ones now are really
dreadful by comparison and very dazzling because they seem to be invariably
badly adjusted as well. Most traffic in Belgium still has conventional
incandescent clear glass headlamps.
Anything other than pure faint red light will rob you of some dark adaption.
But driving with normal headlamps you don't really get anything like dark
enough for fully scotopic vision to be reached. Yellow seems to be a tasteful
engineering compromise that avoids excessive dazzling of other drivers.
Short wavelengths do scatter more in fog so having excess blue light is not
helpful there. And in bad snow storms you get a fair proportion of your own
light output reflected straight back at you.
Regards,
Martin Brown
Daniel Stern Lighting
> Having driven in various countries I have to admit that the French yellow
> filtered headlights are distinctly less painful at night if you are facing
> into a stream of oncoming traffic.
I agree, based on my own subjective perceptions and preferences. But the
question must be asked whether the decrease in glare is primarily due to
the light being yellow rather than white, or if it is primarily due
simply to filtration losses involved in getting yellow (or any other
color, for that matter) from white. It would be fairly simple to test the
question using nothing more specialized than neutral-density filters.
> The odd blue HID ones now are really dreadful by comparison
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 the high blue, violet and/or
near-UV, and those not particularly sensitive to these wavelengths -- with
these sensitivities NOT necessarily being linked! Subjectively, I consider
myself glare-sensitive, but not particularly "blue sensitive", for
instance.
Theoretically, therefore, it is possible that altering the SPD of HID
headlamps so as to reduce the power and prevalence of these wavelengths
could be cut glare substantially without a significant decrease in seeing
light (and possibly an improvement in seeing in bad whether). The
question, assuming this idea were to be supported through further study of
"blue sensitivity", would be how far to go. Would we want to correct back
to a white signal image similar to that produced by ordinary halogen
headlamps? Or would we want to go slightly further into the yellow?
> and very dazzling because they seem to be invariably badly adjusted as
> well.
Even in Europe, with its tighter control of glare in the beam pattern,
mandatory lens cleaners, mandatory automatic headlamp levelling, and
strict periodic vehicle inspections. Fascinating. It's been shown that it
takes less light to to upset drivers accustomed to lower levels of glare
than to upset those accustomed to higher levels of glare. Assuming that's
the phenomenon at work here, then European drivers would probably be
*severely* upset and/or disabled by US HIDs with higher levels of glare in
the beam pattern, no mandatory lens cleaning, no mandatory autolevelling
and lax (or nonexistent) periodic vehicle inspections.
> Anything other than pure faint red light will rob you of some dark adaption.
> But driving with normal headlamps you don't really get anything like dark
> enough for fully scotopic vision to be reached. Yellow seems to be a tasteful
> engineering compromise that avoids excessive dazzling of other drivers.
Subjectively, I agree with you. The politics and history of yellow
headlamp light are very interesting. Unfortunately, because it was
originally a solution to a political problem (albeit an elegant solution
with a solid basis in physiology), the tendency is to dismiss it as
nothing more than an obsolete political artifact. This may amount to
throwing the baby out with the bathwater.
> Short wavelengths do scatter more in fog so having excess blue light is not
> helpful there.
Agreed.
> And in bad snow storms you get a fair proportion of your own
> light output reflected straight back at you.
Agreed. One area in which ECE headlamp standards lag behind the US
standard is in their control of upward stray light (between 10 and 90
degrees up from the horizon). Light cast in this region throws a curtain
in front of the driver's eyes in rain, fog, snow or dust. The US
regulation limits this light to 125 candela per lamp at 12.8V; the ECE
regulation is much higher at 876 candela per lamp at 12V. In practice, the
difference is not as great as it would seem, for two reasons: The US test
procedure for this region is vague and inadequate, and it is often
minimally tested (or tested using a creative interpretation of the
poorly-written letter, rather than the intent, of the regulation). As a
result, many US headlamps produce considerable upward stray light. In
addition, the European low beam pattern's tight/low-light requirements in
the region between the horizon and 10 degrees up often -- but not always
-- have the effect of limiting light higher up as well.
The interesting thing is the ongoing debate about uplight for overhead
signs. US and ECE regulations *BOTH* contain test points in the 2U to 4U,
8L to 8R region, and the minimum allowable values are nearly identical. In
fact, the ECE regulation contains more test points in this region than the
US regulation. The difference is that the allowable *maximum* values in
these areas are much higher in the US standard than in the ECE standard.
Nevertheless, despite essentially identical "You must have at least this
much light in the overhead-sign region" requirements, we still have people
insisting that ECE headlamps prevent the driver from reading overhead
signs. Despite the universality of non-self-illuminated, retroreflective
overhead signs in most countries that use ECE headlamps, we still have
people insisting that ECE headlamps only work because the countries that
use them self-illuminate all their overhead signs.
There is a reality gap.
DS
Arif Khokar
> I think if we had one worldwide standard that basically amounted to the
> bottom areas of BOTH standards' seeing-light zones were chopped off so
> that the minimum acceptable performance were higher, the top area of the
> US standard's glare zone were chopped off so that the maximum acceptable
> glare were lower, and the top area of the ECE standard's upward stray
> light standard were chopped off so that the maximum acceptable backdazzle
> were lower, we'd be pretty much there.
Agreed. Backdazzle can be a problem with both standards. In the
context of HID lamps, there's so much luminance to deal with that the
excess light has to go somewhere... (whether its permitted or not
adequately tested for is pretty much a moot point). I take it that
backdazzle isn't so much of a problem with halogen ECE spec headlamps
(in most cases).
> While the original poster's statement about HID low beams obviating the
> need for high beams is straight out of the HID kit hawkers' bag of hyped
> up nonsense, your "30-35mph" is overstating the case rather severely.
Given that, it looks like I misinterpreted one of your past posts on
this issue. IIRC, my headlamps are about 24 inches off the ground when
mounted. From that, the illuminated distance from the dipped part of
the cutoff is around 200 feet. Given that one needs about a second to
react to a hazard, that probably translates to a safe speed of around 65
mph or so. I still prefer to use my highbeams when I can, though.
Robin Myers
>
> Indeed. That said, I am interested to see what corroboration, if any,
> develops for RPI LRC's study suggesting yellow light (white minus blue)
> may facilitate certain aspects of visual perception related to the driving
> task in a disturbed environment (rain, fog, snow). The interest is not
> just practical (it would tend to explain the otherwise-inexplicably
> persistent preference for yellow fog lamps in the face of regulatory and
> manufacturing preference for white) but historical (it would tend to
> vindicate the French...does anyone want to do that??) 8^{)}
My theory is that the water droplets in fog, rain, etc. scatter more
blue light (just like the water vapor in the atmosphere) and in addition
water absorbs red wavelengths. This scattering creates the glare. By
using yellow lights, red and green wavelengths are added to the scene,
increasing the red and and green wavelengths reflected back to the
viewer and increasing the contrast of objects from the bluer glare
surroundings. Yellow lensed driving glasses also help with
discriminating objects for similar reasons.
Just a theory, but my practical experience with fog lights and yellow
glasses in the notorious Tule fogs of the California Central Valley
tends to agree with the improvement in object discrimination.
Robin Myers
Ricardo
(Stephen H. Westin) wrote:
>> Completely agreed. But there's still a bittuva prisoner's dilemma in
>> so far as having ECE lights does not prevent others from dazzling
>> you with their 900x DoT tikis.
>
>Right. But you can keep from making the problem worse.
True, but at an individual level, that makes precious little overall
difference, hence the prisoner's dilemma. The leaded/unleaded fuel
issue is pretty similar: leaded tends to win out unless it is
heavily taxed, restricted or banned (one person using unleaded won't
make much different to the environment, so might as well use
leaded).
Unfortunately, in North America, there has as yet been no
"internalization" of the negative externality of headlamp glare.
Don Klipstein
>X-No-Archive: Yes
>Daniel Stern Lighting wrote:
>>
>> Yes. The untampered, untinted, unscrewed-up HID burner produces 4100k
>> (nominal). Modifications from this give much less light. Example:
>>Philips and Osram both sell a 6000K burner. Its output is nearly 1000
>> lumens less than that of their 4100K burner.
>
>Just a comment on lumens output.
>
>photopic vision. Our scotopic vision(low illumination) has a increased
>greater illumination relative to lower color temp source with same
>photopic lumens as suggested in this article.
>http://www.electrolink.co.nz/CC256A1C0073A9F5/DCB530D95C0C8EBFCC2569280012C8A6/F0F4FF9DEBDDA1F5CC256A1C0082CF32!Open
>
>^one long line.
>
>So, after including our eye's different spectral sensitivity peak at
>different light level, a higher color temp source with lower photopic
>lumens may provide equal or greater illumination than a lower color temp
>source with higher photopic vision weighed lumens.
>
>consideration.
One extra concern: Photopic vision, which more than scotopic vision
sees detail and color, prefers lower color temperature (warmer color)
lamps of comparable light output. Scotopic vision is generally preferred
and boosted to an extent beyond that indicated by photometric data on the
lamp in question when the color temperature is higher.
Problem is, photopic vision is what sees color and what sees detail.
Scotopic vision will see a sense of illumination and will feed the brain a
sensation of illumination where it plays a significant role. This means
that light which favors scotopic vision (wavelengths from mid-green to
mid-blue) will help you see fog more than it helps you see obstacles
through the fog. Same for any precipitation heavy enough to catch your
attention as to what your headlights are illuminating. Same for you
seeing the countryside illuminated by your headlights and thereby getting
a false sense of safety from extra illumination.
Any extra "illumination power" needs to be directed to where it will
help you avoid a crash and also not into directions that increase the
chance of someone else crashing. This means don't increase illumination
of fog or precipitation more than illumination of objects that you want to
see through fog or precipitation. This means don't achieve extra
illumination of countryside that you won't crash into while making your
eyes see extra illumination that reduces their sensitivity to illumination
where illumination will help you avoid a damaging or dangerous crash.
- Don Klipstein (Jr) - (d...@misty.com)
Daniel Stern Lighting
> Photopic vision, which more than scotopic vision
> sees detail and color, prefers lower color temperature (warmer color)
> lamps of comparable light output. Scotopic vision is generally preferred
> and boosted to an extent beyond that indicated by photometric data on the
> lamp in question when the color temperature is higher.
> Problem is, photopic vision is what sees color and what sees detail.
> Scotopic vision will see a sense of illumination and will feed the brain a
> sensation of illumination where it plays a significant role. This means
> that light which favors scotopic vision (wavelengths from mid-green to
> mid-blue) will help you see fog more than it helps you see obstacles
> through the fog.
Hence:
Driving through fog or snow with good yellow fog lamps = good
Driving through fog or snow with good halogen headlamps = OK
Driving through fog or snow with HID headlamps = ACK!
> Same for you seeing the countryside illuminated by your headlights and
> thereby getting a false sense of safety from extra illumination.
Foreground illumination is famous for creating the illusion of security.
> Any extra "illumination power" needs to be directed to where it will
> help you avoid a crash and also not into directions that increase the
> chance of someone else crashing. This means don't increase illumination
> of fog or precipitation more than illumination of objects that you want to
> see through fog or precipitation. This means don't achieve extra
> illumination of countryside that you won't crash into while making your
> eyes see extra illumination that reduces their sensitivity to illumination
> where illumination will help you avoid a damaging or dangerous crash.
Agreed. Which is why we've gone so badly astray with higher CCT headlamp
light (HIDs and pretend-HID bulbs, legal and otherwise). The increase in
efficacy is terrific, but what was done to the SPD for nothing more than
marketing differentiation reasons ("Nobody will buy a headlamp that works
3 times better if it looks the same, and SAE and ECE 'white' allow us to
go to 10,000K if we want to, so we made it bluer!") is disgraceful.
DS
Don Klipstein
Daniel Stern Lighting wrote (snipped by me wherever I think I snip best):
>On Tue, 7 Jan 2003, Martin Brown wrote:
>> The odd blue HID ones now are really dreadful by comparison
>(which I / Don decides to partially snip)
>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 the high blue, violet and/or
>near-UV, and those not particularly sensitive to these wavelengths -
<total snippage including mention of more-red less bad for night vision>
(I hope I got hings right in terms of Martin Brown saying)
>> Short wavelengths do scatter more in fog so having excess blue light
>>is not helpful there.
>
>Agreed.
And I disagree in part. I insist that all visible wavelengths scatter
surprisingly equally from fog or the like - but scotopic vision sees the
fog more than seeing through the fog, while photpic vsion is better for
seeing through the fog, and among the wavelengths with significant
photopic function (mid-blue through red) photopic/scotopic ratio is
favored by longer waveengths. Photopic/scotopic ratio is favored by
yellow-green through red, and secondarily by violet-blue (but those
wavelengths easily get seen blurry) and is disfavored by wavelengths from
mid-blue to mid-green.
>> And in bad snow storms you get a fair proportion of your own
>> light output reflected straight back at you.
>
>Agreed. One area in which ECE headlamp standards lag behind the US
>standard is in their control of upward stray light (between 10 and 90
>degrees up from the horizon). Light cast in this region throws a curtain
>in front of the driver's eyes in rain, fog, snow or dust. The US
>regulation limits this light to 125 candela per lamp at 12.8V; the ECE
>regulation is much higher at 876 candela per lamp at 12V. In practice, the
>difference is not as great as it would seem, for two reasons: The US test
>procedure for this region is vague and inadequate, and it is often
>minimally tested (or tested using a creative interpretation of the
>poorly-written letter, rather than the intent, of the regulation). As a
>result, many US headlamps produce considerable upward stray light. In
>addition, the European low beam pattern's tight/low-light requirements in
>the region between the horizon and 10 degrees up often -- but not always
>-- have the effect of limiting light higher up as well.
I agree here, favoring ECE.
>The interesting thing is the ongoing debate about uplight for overhead
>signs. US and ECE regulations *BOTH* contain test points in the 2U to 4U,
>8L to 8R region, and the minimum allowable values are nearly identical.
>In fact, the ECE regulation contains more test points in this region than
>the US regulation. The difference is that the allowable *maximum* values
>in these areas are much higher in the US standard than in the ECE
>standard. Nevertheless, despite essentially identical "You must have at
>least this much light in the overhead-sign region" requirements, we still
>have people insisting that ECE headlamps prevent the driver from reading
>overhead signs. Despite the universality of non-self-illuminated,
>retroreflective overhead signs in most countries that use ECE headlamps,
>we still have people insisting that ECE headlamps only work because the
>countries that use them self-illuminate all their overhead signs.
Or that in the USA "America Knows Best". It seems obvious to me that
even rather black blacktop scatters upward enough light from low beams to
illuminate overhead signs.
Or are USA voters who drive so stupid as to not pester their elected
politicians and would-be campaigning elected politicians to so much as
let them see on the road at night as well as people do in most countries
other than the USA? Are USA voters so stupid as to have no concern other
than whose ox gets gored somewhere other than the USA roadways which for
decades have been in the Top 10 causes of death, above homicide and war
even, among USA residents?
>There is a reality gap.
>DS
- Don Klipstein (d...@misty.com, http://www.misty.com/~don/index.html)
Daniel Stern Lighting
> >> Short wavelengths do scatter more in fog so having excess blue light
> >>is not helpful there.
> >
> >Agreed.
>
> And I disagree in part. I insist that all visible wavelengths scatter
> surprisingly equally from fog or the like
I agree with you. I should've been more clear, my "agreed" referred to
"having excess blue light is not helpful [in fog]". Rayleigh Scattering
does not occur at the droplet sizes typical of roadway weather conditions.
> - but scotopic vision sees the
> fog more than seeing through the fog, while photpic vsion is better for
> seeing through the fog, and among the wavelengths with significant
> photopic function (mid-blue through red) photopic/scotopic ratio is
> favored by longer waveengths.
In a word: Yellow!
> >despite essentially identical "You must have at
> >least this much light in the overhead-sign region" requirements, we still
> >have people insisting that ECE headlamps prevent the driver from reading
> >overhead signs. Despite the universality of non-self-illuminated,
> >retroreflective overhead signs in most countries that use ECE headlamps,
> >we still have people insisting that ECE headlamps only work because the
> >countries that use them self-illuminate all their overhead signs.
> Or that in the USA "America Knows Best".
That attitude is sadly prevalent in North American regulatory bodies.
> It seems obvious to me that even rather black blacktop scatters upward
> enough light from low beams to illuminate overhead signs.
I agree, but this idea is regarded as heresy. I put it in version 1 of
WDTGCF. It got the report barred from eyes that needed to read it, so I
took it out in version 2, even though engineers from the two companies
that make most of the retroreflective sheeting used on US overhead signs
privately said "You're right about that."
> Or are USA voters who drive so stupid as to not pester their elected
> politicians and would-be campaigning elected politicians to so much as
> let them see on the road at night as well as people do in most countries
> other than the USA?
For one, most American drivers don't know there's something better than
constant glare and beam patterns that throw light to the wrong places. For
two, those who have experience with ECE headlamps and find them better get
told by officials "It's all in your head, they're not better." For three,
US automakers who like the comparatively-lax US headlamp standard trot out
all manner of "proof" which, to read it, you'd logically conclude that the
nighttime highway outside North America is a river of blood from all the
crashes caused by ECE headlamps.
> Are USA voters so stupid as to have no concern other than whose ox
> gets gored somewhere other than the USA roadways which for decades
> have been in the Top 10 causes of death, above homicide and war even,
> among USA residents?
NHTSA continues to claim that US roadways and US cars are "the safest in
the world". The numbers prove them wrong, but this is of little
consequence to those who insist that all overhead signs outside North
America are self-illuminated, that Europeans use their low beams only in
the city and their high beams on the highway regardless of traffic
density, that overhead road signs are invisible without self-illumination
or US headlamps, that there's proof showing a safety benefit to headlamps
that throw tons of light upwards, and, presumably, that the moon is made
out of green cheese.
Steven Reiter
--
Steven Reiter
Lewisville, Texas
"Daniel Stern Lighting" <das...@vrx.headlamp.net> wrote in message
news:Pine.SOL.4.33.03010...@alumni.engin.umich.edu...
> The original poster has a hard-on for HID. It doesn't seem to matter to
> him that what he's doing will not give him lighting that is, in any real
> sense, "better" than what he has.
The HIDs that I installed on my truck are a quantum-leap type of improvement
over the stock lamps. I can see much further and much more clearly in front
of and to the right side of the vehicle.
To my knowledge, this vehicle is not sold in Europe. No E-Code lights. The
only E-code way to go is with the base model headlight housings and a pair
of Hella European H4 large rectangular headlights.
As far as a good set of auxiliary lamps, I run a pair of Hella Micro FF
foglamps and they help to the sides, but can't hold a candle to the HID
flamethrower low beams.
Steve
Steven Reiter
visible light output...?
And if aligned properly, the 9006 HID fitment should be very close to the
original 9006 halogen specs...?
That's what I needed to know.
Any companies that you recommend for sourcing this stuff?
Thanks,
Steve
--
Steven Reiter
Lewisville, Texas
"Daniel Stern Lighting" <das...@vrx.headlamp.net> wrote in message
news:Pine.SOL.4.33.03010...@alumni.engin.umich.edu...
Daniel Stern Lighting
> > The original poster has a hard-on for HID. It doesn't seem to matter to
> > him that what he's doing will not give him lighting that is, in any real
> > sense, "better" than what he has.
> The HIDs that I installed on my truck are a quantum-leap type of improvement
> over the stock lamps.
It is doubtful that this is true. It is also doubtful that you are
qualified to make any but purely subjective statements on the matter.
> To my knowledge, this vehicle is not sold in Europe. No E-Code lights.
E-code aero headlamps *do* exist for this vehicle.
> only E-code way to go is with the base model headlight housings and a pair
> of Hella European H4 large rectangular headlights.
And this would be bad because...?
> foglamps and they help to the sides, but can't hold a candle to the HID
> flamethrower low beams.
Throwing flames right into other drivers' eyes. Shame on you.
DS
Daniel Stern Lighting
> And if aligned properly, the 9006 HID fitment should be very close to the
> original 9006 halogen specs...?
Do not put words in my mouth. This is not true, and I and others have told
you that. You're intent on ignoring everything that doesn't agree with
your dumb ideas.
> Any companies that you recommend for sourcing this stuff?
Yeah, right.
DS
> "Daniel Stern Lighting" <das...@vrx.headlamp.net> wrote
> > > Photopic vision, which more than scotopic vision
Steven Reiter
I can see clearly at night.
Steve
--
Steven Reiter
Lewisville, Texas
"Daniel Stern Lighting" <das...@vrx.headlamp.net> wrote in message
news:Pine.SOL.4.33.030108...@alumni.engin.umich.edu...
Martin Brown
Daniel Stern Lighting wrote:
> On Wed, 8 Jan 2003, Don Klipstein wrote:
>
> > >overhead signs. Despite the universality of non-self-illuminated,
> > >retroreflective overhead signs in most countries that use ECE headlamps,
> > >we still have people insisting that ECE headlamps only work because the
> > >countries that use them self-illuminate all their overhead signs.
I don't know where this one comes from. Some overhead signs on the largest
motorway interchanges and in major city centres are self illuminated, but by far
the majority of roadsigns are passive reflective. ECE headlamps have no problems
at all illuminating them except in the minds of US automaker lobby groups.
> > Or are USA voters who drive so stupid as to not pester their elected
> > politicians and would-be campaigning elected politicians to so much as
> > let them see on the road at night as well as people do in most countries
> > other than the USA?
>
> For one, most American drivers don't know there's something better than
> constant glare and beam patterns that throw light to the wrong places.
I have wondered about that when driving in the USA. It seems to me like all
vehicles there have badly adjusted headlamps (though some are worse than
others). And a few are derelict rust buckets - is there no vehicle compliance
inspection at all? Also there seems to be no restriction on the number and type
of distracting flashing advertising things people can put up to disguise traffic
lights and junctions at night.
It isn't impossible to fit ECE compliant headlamps to modern US made vehicles
there are some driving around Brussels. Though why anyone would bother to drive
them in Europe is another question.
> For two, those who have experience with ECE headlamps and find them better get
>
> told by officials "It's all in your head, they're not better." For three,
> US automakers who like the comparatively-lax US headlamp standard trot out
> all manner of "proof" which, to read it, you'd logically conclude that the
> nighttime highway outside North America is a river of blood from all the
> crashes caused by ECE headlamps.
Same sort of "proof" as they used to trot out against fitting seatbelts in cars
?
> > Are USA voters so stupid as to have no concern other than whose ox
> > gets gored somewhere other than the USA roadways which for decades
> > have been in the Top 10 causes of death, above homicide and war even,
> > among USA residents?
>
> NHTSA continues to claim that US roadways and US cars are "the safest in
> the world". The numbers prove them wrong, but this is of little consequence
Why can't this be challenged head on? Seems to me like they cannot defend this
position.
http://www.scotland.gov.uk/library2/doc05/ras-11.htm
The only copy of the stats I found quickly online isn't ideal but shows the
range. USA isn't even close to best practice. The rate of fatalities shoots up
in countries where drink driving is still endemic.
Regards,
Martin Brown
Brandon Sommerville
<superdu...@earthlink.net> wrote:
>I am sooooo ashamed...
You should be.
>I can see clearly at night.
And screw everyone else who can't due to your actions, right?
--
Brandon Sommerville
remove ".gov" to e-mail
The easy way is always mined.
Stephen H. Westin
> Daniel Stern Lighting wrote:
> >
> > Indeed. That said, I am interested to see what corroboration, if any,
> > develops for RPI LRC's study suggesting yellow light (white minus blue)
> > may facilitate certain aspects of visual perception related to the driving
> > task in a disturbed environment (rain, fog, snow). The interest is not
> > just practical (it would tend to explain the otherwise-inexplicably
> > persistent preference for yellow fog lamps in the face of regulatory and
> > manufacturing preference for white) but historical (it would tend to
> > vindicate the French...does anyone want to do that??) 8^{)}
>
> My theory is that the water droplets in fog, rain, etc. scatter more
> blue light (just like the water vapor in the atmosphere) and in addition
> water absorbs red wavelengths.
But that's obviously not true, or at least not significant. What color
is a cloud? White or gray. What color is fog? White or gray. Not blue.
This shows that the scattering involved has only a weak dependence on
wavelength.
The particle size just isn't right for Rayleigh scattering in the
visible wavelengths. Rayleigh scattering is what makes the sky blue;
if fog were scattering the same way, it would be blue, too.
<snip>
stanislav shalunov
> http://www.scotland.gov.uk/library2/doc05/ras-11.htm
This talks about fatalities per capita and vehicle. I bet the
U.S. would look more favorably if fatalities per vehicle-kilometer
traveled were considered. In fact, it does: according to
<URL:http://www.tc.gc.ca/roadsafety/vision/2000/en/RSV-22a.htm>
it's far from being the safest, but is somewhat better than Canada,
Australia or Germany. The range of variation is small: only a factor
of two between the safest listed (UK) and the most dangerous (Japan).
Such a difference might be attributed to a number of factors.
A report at
<URL:http://www.rws-avv.nl/verkeersveiligheid/rapporten/Paper-CMRSCXII-sustainablesafety-alexvanloon-010517.pdf>
(published a year earlier) seems to give somewhat different order, but
comparable numbers (see especially page 4).
What does comparing fatality rates per X of different countries prove?
Reducing the number of road fatalities per capita and per registration
is not hard: simply discourage driving (in favor of taking the public
transportation, staying home, or living in a smaller country). The
most efficient way to discourage driving long distances is likely to
be to not have them in your country. The second-best way is probably
pushing people to stay home or take the train/fly by having higher
gasoline taxes.
--
Stanislav Shalunov http://www.internet2.edu/~shalunov/
This message is designed to be viewed at 600 dpi.
William H. Hathaway
(much clipped...)
>
> a false sense of safety from extra illumination.
>
> Any extra "illumination power" needs to be directed to where it will
> help you avoid a crash and also not into directions that increase the
> chance of someone else crashing. This means don't increase illumination
> of fog or precipitation more than illumination of objects that you want to
> see through fog or precipitation. This means don't achieve extra
> illumination of countryside that you won't crash into while making your
> eyes see extra illumination that reduces their sensitivity to illumination
> where illumination will help you avoid a damaging or dangerous crash.
>
Sorry to abruptly change direction here, but this sounds _so_ much
like what astronomers have been saying for decades. The _illusion_
of safety from gawsh-awful glaring streetlights that send expensive
energy up into the sky at the speed of light. People get the illusion
of being 'safer', but it's a big crock. Yet I bet there is not one
politician out of 1000 that knows diddly-squat about light pollution.
(Recently one of them commented on how pathetic North Korea was because
on night satellite photos, they were dark, while every other country
around was brightly lit. Well, NK is pathetic, but all that light
up into the sky is incredibly wasteful, not something to be proud of.)
As for safety, I still have the newspaper clipping of the woman in
Washington DC who, when commenting on her male companion being shot to
death on the street, saying 'We didn't think anything would happen - we
were right under a streetlight.' Illumination. Illusion.
I should add that after one of the last star parties I went to, my
g'friend had me track down the searchlight in the sky so we could
see the plasma arc up close. (It was cloudy by then, so I couldn't
object.) Some people do get turned on by powerful photon cannons.
While there (an attraction to a night club), we watched as police/security
guys chased some guys driving away quickly. Handguns deployed even.
All that light and safety. Draws idiots as well as light fanatics.
Back to your discussion about car head lamps.
Wm. H.
Matthew Russotto
William H. Hathaway <hath...@stsci.edu> wrote:
>
>(Recently one of them commented on how pathetic North Korea was because
>on night satellite photos, they were dark, while every other country
>around was brightly lit. Well, NK is pathetic, but all that light
>up into the sky is incredibly wasteful, not something to be proud of.)
Unfortunately NK isn't not lit because they've figured out some way to
control light pollution. They're not lit because they've got no light.
--
Matthew T. Russotto mrus...@speakeasy.net
"Extremism in defense of liberty is no vice, and moderation in pursuit
of justice is no virtue." But extreme restriction of liberty in pursuit of
a modicum of security is a very expensive vice.
Marc
>I am sooooo ashamed...
>
>I can see clearly at night.
You are like the loser I flashed the other night. He had on his
driving lights/fog lights. Whatever they were, they were aimed up
into oncoming traffic. I flashed him. He flashed back with his
brights. They were less offensive than his aux lights.
"I want light. Fuck everyone else."
Marc
For email, remove the first "y" of "whineryy"
Marc
>In article <3E1CDCDF...@stsci.edu>,
>William H. Hathaway <hath...@stsci.edu> wrote:
>>
>>(Recently one of them commented on how pathetic North Korea was because
>>on night satellite photos, they were dark, while every other country
>>around was brightly lit. Well, NK is pathetic, but all that light
>>up into the sky is incredibly wasteful, not something to be proud of.)
>
>Unfortunately NK isn't not lit because they've figured out some way to
>control light pollution. They're not lit because they've got no light.
Tucson residents seemed proud of their laws regarding light pollution.
I was able to see pretty well looking up, but the area is low
pollution and low humidity, so I don't know whether the laws helped
that much or not. The resident's comparison of before and after
seemed to indicate so.
Floyd Rogers
> "Steven Reiter" <superdu...@earthlink.net> wrote:
> >I am sooooo ashamed...
> >
> >I can see clearly at night.
>
> You are like the loser I flashed the other night. He had on his
> driving lights/fog lights. Whatever they were, they were aimed up
> into oncoming traffic. I flashed him. He flashed back with his
> brights. They were less offensive than his aux lights.
>
> "I want light. Fuck everyone else."
Sounds like the guy in the Tahoe that followed me yesterday: some
sort of over-wattage bulbs in his headlights, fogs lights on. Bright
daylight (maybe the nice weather up here in Seattle in January surprised
him?) Tailgating me, too.
Floyd
Robin Myers
>
> Robin Myers <ro...@rmimaging.com> writes:
>
> > Daniel Stern Lighting wrote:
> > >
> > > Indeed. That said, I am interested to see what corroboration, if any,
> > > develops for RPI LRC's study suggesting yellow light (white minus blue)
> > > may facilitate certain aspects of visual perception related to the driving
> > > task in a disturbed environment (rain, fog, snow). The interest is not
> > > just practical (it would tend to explain the otherwise-inexplicably
> > > persistent preference for yellow fog lamps in the face of regulatory and
> > > manufacturing preference for white) but historical (it would tend to
> > > vindicate the French...does anyone want to do that??) 8^{)}
> >
> > My theory is that the water droplets in fog, rain, etc. scatter more
> > blue light (just like the water vapor in the atmosphere) and in addition
> > water absorbs red wavelengths.
>
> But that's obviously not true, or at least not significant. What color
> is a cloud? White or gray. What color is fog? White or gray. Not blue.
> This shows that the scattering involved has only a weak dependence on
> wavelength.
>
> The particle size just isn't right for Rayleigh scattering in the
> visible wavelengths. Rayleigh scattering is what makes the sky blue;
> if fog were scattering the same way, it would be blue, too.
I was trying to be brief and encourage more discussion on this topic.
Rayleigh scattering is accepted as the phenomenon accounting for the
blue sky. In all of the references I have, the cause of Rayleigh
scattering is attributed to "particles" in the atmosphere of up to 1/2
the wavelength of the light. Lord Rayleigh was able to show that
statistical variance in the refractive index of a homogenous gas would
produce wavelength dependent scattering. However, none of the references
states that scattering from the basic oxygen and nitrogen molecules is
the sole reason for the blue sky. Since our atmosphere contains a
measurable percentage of water vapor, then it too must contribute to
Rayleigh scattering. Since water absorbs red wavelengths, is it possible
that the absorption is also part of the mechanism?
Clouds and fog are generally attributed to Mie scattering, which is the
model used for particles from 1/2 the light wavelength up to about 2
times the wavelength. Mie scattering shows that most of the light is
scattered away from and some back toward the light source. There are
also intensity lobes of green and red wavelengths that are scattered
toward the sides (a phenomenon which has been used to determine the size
of the scattering particles). When the size of the particles is
increased beyond the range for Mie scattering, and especially when the
particles are of varying size, all wavelengths are equally dispersed,
thus leading to the white or gray color for clouds and fog.
However, experiential evidence with fog lights (here we go back on
topic) seems to show that Mie scattering is not the sole mechanism in
effect. If so, then any color light would equally disperse in a fog and
add to the glare. Instead, objects do appear more distinctly with yellow
fog lights. So, if we were to assume some Rayleigh scattering as well as
Mie, then that might account for yellow fog lamp light being less
dispersed and contributing to the detection of objects. It has also been
postulated in this thread that the improvement of the photopic
perception by using yellow lights is the sole reason. My postulation is
that there may be another physical mechanism at work besides these
phenomena; namely that the absorption by water of red wavelengths means
that for a given amount of white light more blue would be reflected back
to the viewer and when combined with Rayleigh and Mie scattering, as
well as reduced photopic perception of blue wavelengths, results in more
glare. Using yellow fog lights means more yellow light is reflected from
objects in the fog and improves the signal to noise ratio for our more
sensitive middle and long wavelength photopic vision.
In all of the Rayleigh and Mie formulas, only the particle sizes and
refractive indices are used, not the spectral transmission/absorption
characteristics and I find that very odd. It is just my experience that
leads me to believe that more than these two physical attributes should
be contributing to the final result. Just a theory. I'd be interested in
any experiments that disprove this.
Robin Myers
References:
"Color and Light in Nature", David K. Lynch and William Livingston,
Cambridge University Press, 1995, ISBN 0-521-46836-1, pages 21-33.
"The Physics and Chemistry of Color; The Fifteen Causes of Color", Kurt
Nassau, Wiley Interscience, 1983, ISBN 0-471-86776-4, pages 232-240,
Appendices A and C.
"Colour and the Optical Properties of Materials", Richard Tilley, John
Wiley and Sons, 2000, ISBN 0-471-85198-1, pages 108-118.
Ricardo
>Tucson residents seemed proud of their laws regarding light pollution.
But they shouldn't be so proud of the fact that some of them can't
even spell their home town's name! (Yes, I saw a local misspell it
[in writing] on the TV; the inevitable swap of the C and S.)
Steven Reiter
remember it, alright...
I run 3 GE4522 aircraft landing lights tied into my high beam circuit.
They're only 250 watts apiece and are excellent for use with the high beams
as the HIDs are quite sufficient with low beams. They provide an
appropriate kick to the halogen high beams.
The nice thing is that since the HIDs do so much better a job of
illumination, I don't have to kick on the high beams very often. I can now
drive up to 80 mph at night and not be worried about outdriving my low
beams, whereas before above 50 mph was scary.
But alas, according to Daniel, I am not qualified to make subjective
comments like this...
Silly me...
Steve
--
Steven Reiter
Lewisville, Texas
"Floyd Rogers" <flo...@accessone.com> wrote in message
news:v1r6em4...@corp.supernews.com...
Nathan Nagel
beams just as much as your high beams. Heck, a new Ford truck is
painful to look at even without a shitty aftermarket HID kit. Sadly,
most new car headlights are shite.
nate
Daniel Stern Lighting
> The nice thing is that since the HIDs do so much better a job of
> illumination, I don't have to kick on the high beams very often. I can now
> drive up to 80 mph at night and not be worried about outdriving my low
> beams
Wrong. You can't. The illumination range of low beam headlamps is limited
due to *geometric* factors, not illuminance factors.
> But alas, according to Daniel, I am not qualified to make subjective
> comments like this...
Quote me properly. What I said was that you are qualified *ONLY* to make
unscientific subjective comments, not valid analyses of headlamp
performance.
DS
Nathan Nagel
Daniel Stern Lighting wrote:
>
> On Sat, 11 Jan 2003, Steven Reiter wrote:
>
> > The nice thing is that since the HIDs do so much better a job of
> > illumination, I don't have to kick on the high beams very often. I can now
> > drive up to 80 mph at night and not be worried about outdriving my low
> > beams
>
> Wrong. You can't. The illumination range of low beam headlamps is limited
> due to *geometric* factors, not illuminance factors.
>
Well, if he used a drop in HID kit in his stock lights, he may very well
be able to see farther on low beam... at the expense of the retinas of
oncoming drivers.
nate
Brandon Sommerville
<superdu...@earthlink.net> wrote:
>No, if it was me, you'd likely have long-term dalmatian vision. You'd
>remember it, alright...
>
>I run 3 GE4522 aircraft landing lights tied into my high beam circuit.
>They're only 250 watts apiece and are excellent for use with the high beams
>as the HIDs are quite sufficient with low beams. They provide an
>appropriate kick to the halogen high beams.
>
>The nice thing is that since the HIDs do so much better a job of
>illumination, I don't have to kick on the high beams very often. I can now
>drive up to 80 mph at night and not be worried about outdriving my low
>beams, whereas before above 50 mph was scary.
>
>But alas, according to Daniel, I am not qualified to make subjective
>comments like this...
And what about people you're driving either towards or behind? Oh,
right, you can see now so screw everyone else. I don't know how I
forgot that.
Arif Khokar
> I run 3 GE4522 aircraft landing lights tied into my high beam circuit.
> They're only 250 watts apiece and are excellent for use with the high beams
What gauge wire are you "feeding" those lamps with?
Marc
>On Thu, 09 Jan 2003 00:56:08 -0900, Marc <whin...@yifan.net> wrote:
>
>>Tucson residents seemed proud of their laws regarding light pollution.
>
>But they shouldn't be so proud of the fact that some of them can't
>even spell their home town's name! (Yes, I saw a local misspell it
>[in writing] on the TV; the inevitable swap of the C and S.)
Sounds like a TVR. Yeah, that's a stretch trying to bring it back to
driving...
Ricardo
>>But they shouldn't be so proud of the fact that some of them can't
>>even spell their home town's name! (Yes, I saw a local misspell it
>>[in writing] on the TV; the inevitable swap of the C and S.)
>
>Sounds like a TVR.
DNA = National Dyslexic Association ;)
>Yeah, that's a stretch trying to bring it back to
>driving...
Héhé, don't worry, I can do the same right now with another example:
the IVR code for Canada is CDN (why not CAN or CND, beats me).
Steven Reiter
wire. Each light also has a 30A fuse fed directly off a 5 terminal power
distribution block at the passenger side battery. Each light has a large
ground lug attached to one of the core support attachment bolts.
Triggering for the relays is from the high beam power wire.
Steve
--
Steven Reiter
Lewisville, Texas
"Arif Khokar" <akhok...@wvu.edu> wrote in message
news:v1vi2lg...@corp.supernews.com...
Marc
>On Fri, 10 Jan 2003 22:54:04 -0900, Marc <whin...@yifan.net> wrote:
>
>>>But they shouldn't be so proud of the fact that some of them can't
>>>even spell their home town's name! (Yes, I saw a local misspell it
>>>[in writing] on the TV; the inevitable swap of the C and S.)
>>
>>Sounds like a TVR.
>
>DNA = National Dyslexic Association ;)
>
>>Yeah, that's a stretch trying to bring it back to
>>driving...
>
>Héhé, don't worry, I can do the same right now with another example:
>the IVR code for Canada is CDN (why not CAN or CND, beats me).
CanaDiaN.
Even a member of the DNA can get that one...
Ricardo
>>Héhé, don't worry, I can do the same right now with another example:
>>the IVR code for Canada is CDN (why not CAN or CND, beats me).
>
>CanaDiaN.
>
>Even a member of the DNA can get that one...
Sure, but normally the tag abbreviation represents the country, not
the nationality, e.g. USA for United States of America, IRL for
IReLand, CH for Confœderatio Helvetia, and so on. So the system's
totally illogical. :)