Sylvania Silverstar headlamp bulbs

Stand by for extensive comments by Daniel Stern.

-=-
Alan

 

Just replaced the stock headlight bulbs on my 97 Cirrus with Sylvania
Silverstars. The vehicle had the problem common to a lot of these cars -
the lenses cloud up with age, and the stock lamps were poor to start with.

Initial assessment of new lamps is that they provide a nice even light in
front of car. Visibilty on low beams is better side to side, and a fair
improvement in distance. High beams are quite good for distance. I drive
twenty-five miles through a wooded highway every day, and moose are a
definite concern. So, all in all, I think the Silverstars will help some
with visibility. I'm not sure if they are worth the added expense over
cheaper high-output lamps, although the white light seems to be a definite
improvement.

Norm.

 

Hate to break the bad news to you, but the bulbs you installed produce
*less* light than regular, standard bulbs, and much less light than
Sylvania's Xtravision bulb line. Blue coatings on bulbs NEVER improve
headlamp performance, ever. They color the light -- that's all they do. A
high-efficiency filament is used in these bulbs because the blue
filtration coating steals so much light that the hi-po filament is needed
to get minimum legal levels of light through the filter.

No 9007 bulb changes the beam pattern of your headlamps (well, except for
the crappy 3rd-world ones which make it even worse than it was). The beam
pattern is a function of the optics.

Wishful thinking, optical illusion. Your distance vision and the beam
spread are, at *very* best, identical to what they were before.

Even more so now that you've reduced the output of your headlamps, and
doubly more so now that you're full of false confidence in your
nonexistent "better" visibility.

When they burn out shortly -- they have to drive the snot out of the
filament to get legal light levels through the filter -- let us know your
opinion on that matter.

The "whiteness" of the light does not improve your ability to see. I'm
afraid you've bought into pseudoscientific marketing hype and perhaps have
a bit of the "Slick-50 effect" going on: Of *course* your can see better,
you just spent $50 on seeing better!


Much more detailed analysis here:

http://tinyurl.com/rzl5


DS

 

That may not be correct.

Not that this is a topic of much interest to me, but there are a
multitude of sunglasses out there that have all sorts of effects on
daytime driving. Remember the "blu-blockers" ?

Your eyes, like your ears, do not have a flat frequency response and
the intensity of light from different sources (that have different
color temperatures) as measured by a light meter does not equate very
well with how your eyes sense intensity (unless there are meters that
are calibrated in terms of sensitivity curve of the human eye).

I believe it's been theorized (or proven?) that glare, for example, is
caused predominantly by the short(er) wavelengths (ie towards the blue
end) hence blu-blockers claim to block blue light therefore allowing a
clearer image to form on our retinas.

It stands to reason that IF indeed there is an optimal spectra to
illuminate a scene and render that scene in our eyes, then that same
spectra should be what our headlights produce.

I for one find the new(er) "blue" headlights to be "easier on the
eyes" when faced with the light from on-coming traffic. Perhaps it's
because human eyes are less sensitive to the shorter wavelengths and
hence the blue lights really are less bright as far as the human eye
is concerned. Some people (older people?) or people with thinner
corneas or perhaps artificial implanted lenses are, I believe, *more*
sensitive to the shorter wavelengths and hence may find blue
headlights to be brighter, to the point of being irritating... ?

 

Try for comparisons sake using an adjusted red light so that it displays the
same amount of lumens and a white light putting out the same lumens. Which
one do you think will make it easier to see? In our basement a bit ago the
light burnt out so we replaced it one the same wattage and stuff but we used
a different brand that's not as "white" (GE vs. generic) as the one that
was burnt out and it's noticeably darker even though it's the same wattage
and stuff.

 

Invalid comparison. We're talking different compositions of white here,
not white vs. single-color.

Wattage is not a measure of light output, and there is enormous variance
in the luminous flux (lumens, the measure of light output) produced by
bulbs of the same wattage -- all you've shown is that name-brand bulbs
generally have higher efficacy (lumens per watt) than generic ones, not
that "whiter" light is better for seeing.

DS

 

Anything anyone says may or may not be correct, but in this case, it is.

Yes. They *removed* blue from the light reaching the eyes. Same deal as
the French Selective Yellow headlamps and foglamps of 1936 to 1993, and
opposite the effect of these blue-filtered bulbs that remove yellow.

Most photometers used for purposes of predicting how well a light source
will work for a given task are specifically calibrated to v-lambda (the
photopic or "daytime" sensitivity curve of the human eye) or v'-lambda
(the scotopic or "nighttime" sensitivity curve of the human eye),
depending on what needs to be measured and predicted.

The human eye has a great deal of trouble processing wavelengths in the
blue-to-violet. If you've ever looked at the blue runway lights as your
plane taxis in or out at night, you've probably noticed they're much
harder to focus on and appear fuzzy at the edges compared to the amber
ones and the green ones. Blue light also causes disproportionately higher
levels of glare -- the headlamp bulbs under discussion have been found to
produce approximately 50% more glare than unfiltered, clear-glass bulbs
for any given intensity level.

This is all backwards, and contains several variables. It's entirely
possible that the "new(er) 'blue' headlights" you find easier on the eyes
are in fact genuine HID headlamps, many of which direct less light than
halogen headlamps towards oncoming traffic.

It's been shown repeatedly that bluer light = more glare for a given
intensity (Sullivan, J. M.; Flannagan, M. J. 2001. Visual effects of
blue-tinted tungsten-halogen headlamp bulbs. Michigan University, Ann
Arbor, Transportation Research Institute, Human Factors Division. 28 p.
UMTRI-94291 , or just read the pertinent parts in attachment 3 of
http://www.pergolesi.demon.co.uk/dastern/ )

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 especially "blue sensitive", for
instance. That means -- as I suspect is the case with you -- that
properly-aimed, well-designed HID headlamps don't bother me, but
poorly-designed or misaimed headlamps of pretty much any type definitely
do.

Researchers are currently working on tweaking the output spectrum of
automotive HIDs to eliminate the useless-for-seeing spike in the high blue
which causes this reaction. The difficulty is that the removal of Mercury
from HID chemistry, which is desired by various countries with automotive
end-of-life recycling regulations, tends to shift the output spectrum
*more* towards blue.

But none of this is completely relevant to the topic at hand:
Blue-filtered headlamp bulbs increase glare without increasing seeing, and
they certainly don't make the magical improvements to the beam pattern
claimed by the original poster.

DS

 

I agree with Dan 100 percent...

 

I installed a set of 9007 on my 1999 dodge grand caravan. what a waste
of money. less light then before...Should have listened to DAN...I
would have more in my walet now....

 

I am very sensitive to blue light glare; I hate it. Some HID lights are fine
and some drive me up the wall. The new Chrysler Pacifica is bad, Audi's are
bad, many other's don't hit me with that blue glare. It seems that some
designers know how to get this right. The other's should be shot.

Richard.

 

Some automakers specifically ask lamp makers to provide a "blue flash"
effect at the top of the beam pattern, others don't specify one way or
another, and still others will not accept lamps that exhibit such an
effect.

Yes, it ought to be illegal.

DS

 

The point I was trying to make is that if the light outputs are the exact
same what one would make it easier to see? The red or the white? You don't
even have to use the color red, you could use a shade of white that's darker
then pure white. I'll admit that the whiteness of light doesn't affect your
ability to see into the distance but at close ranges it does play a role.
I'll also admit that whiter lights don't really do anything for people
driving cars (got a lil bit carried away there thinking about my headlights
on my 93 GP). Back to my point though, given 2 lights where their outputs
are identical measured outside the bulb, with one being darker then the
other, the lighter of the 2 bulbs will make it easier to see the immediate
surroundings.

 

And the point *I* am making is that the point *you* are making is
irrelevant to the discussion at hand.

Sorry, no. It doesn't.

"darker" and "lighter" are not characteristics of light.

DS

 

It is too relevant. Were you not the one that brought up "whiteness" not
doing anything? I'm saying that the "whiteness" can play a role.

How so? Flourescant lights are "whiter" then incandescant lights. In my
bedroom I have incandescants and I can't see things like slight
discolorations on my pants until I go to school and see it under the
flourescant lighting. Can't see it inside with any incandescant, yet outside
I can see it. Isn't the suns light regarded as the whitest?

Different example, go outside to an empty road, parking lot or something in
the city (where they use the sodium vapor lights) and look at the ground
under a streetlight looking for something small like an ear ring stud and
bring along a flashlight. Put the stud on the ground and get a look at it
with the streetlight then shine the flashlight on it. The "whiter" light
from the flashlight will make it easier to see the stud on the ground.

 

I have often found that shining a flashlight almost horizontally along
the ground often works better. So I think that the angle from which the
illumination comes makes a difference too -- and you can't alter the
angle of the street lights.

-=-
Alan

 

On Thu, 23 Oct 2003, Phillip Schmid wrote:

You want me to explain the physiology of human eyesight?

No, they're not.

The sun's light under certain conditions is taken as the 1.00 Color
Rendering Index (CRI) standard. However, there is no such thing as the
"whitest" light. It sounds like you have some desire to know what you're
talking about. I recommend you learn about Color Rendering Index,
Correlated Color Temperature, Illuminant D65, and the CIE light color
charting system and standard chart.

No, the much higher CRI of the flashlight will make it easier to see the
stud on the ground.

DS

 

I'd be surprised if either of you were right: the constantly moving
location of the flashlight will make the stud easier to see.

 

So what bulb do you recomend ?

KS

 

Depends what kind of car is in question.

DS

 

2003 Town and Country, 2002 Stratus