Yellow vs white fogs and a way to switch them

[IdahoDoug]

Many of you know I own a business that installs 3M Clear Bras and headlamp protection for area dealerships as well as my main gig. In keeping with being on the cutting edge, I obtained some of the latest headlamp film (non-3M unfortunately) to test on my cars before offering it as a new feature to my clients. The film comes in grey, faint blue and amber. I was interested in the amber for offering to turn factory white fogs yellow while also providing the energy absorbent protection of the film.

As a test, I put the film on on of my Subaru's Hella FF200 fog lamps and I was quite impressed. I was expecting it to be the tacky orange color you see on Kmart (sorry Kmart) foglamps, rather than the deep yellow of a quality European foglamp. But it is indeed a perfect replica of the correct shade, so they did their homework. As a comparo, this evening I swapped the bulb of the other still white FF200 with a Hella Yellow Star, which puts out that yellow beam by itself. Survey says? - The beam colors are indistinquishable at night from about 50 meters - same color. It's uncanny.

My question for the forum is this. Once you alter the light frequency, you alter it, no matter how you did it, right? Of course it would take a light meter to determine which strategy knocked the most lumens out of it, but other than that, the yellow beam's effectiveness should be the same whether you colored it with a bulb next to the white filament, or used my strategy with the lense - right? Am I missing anything here?

Then I played with the blue film. It makes a normal halogen bulb put out light that is distinctly whiter and has the ol' HID appearance. Coincidentally, I was then perusing some Hella literature while sitting on the can taking a Beowulf and Hella is now offering blue lenses about the same shade. Hmmmm. I'm starting to get the impression that changing the color of a lamp's output can be accomplished with true optical grading by using film and lenses vs the coated bulbs. So I got up and wiped my Junk and went to look for other films.

Can anyone think of a reason that this would not be true? Seems too stupid and easy, but to my eyes there is no question the yellow film is right on. And the blue film also shifts the normal yellowish bulbs to a clean white you'll immediately notice if that's your thing (it's not mine).

The film itself is near optical grade for clarity and surface. I'm testing it for abrasion, heat and thermal stability at the moment.

So what do you guys think of this stuff from a physics perspective? Can I be looking at two identical colored light beams that use different strategies to achieve them and assume their output is therefore functionally identical?

That oughta keep you guys busy....

DougM

 

[jwest]

Let's take a look at what's out there.
Lightforce offers interchangable filters to suit different conditions.

Once you alter the light frequency, you alter it, no matter how you did it, right? Of course it would take a light meter to determine which strategy knocked the most lumens out of it, but other than that, the yellow beam's effectiveness should be the same whether you colored it with a bulb next to the white filament, or used my strategy with the lense - right?

Sure.
Filters have been used in photography for decades as a way of changing the characteristics of light. Sunglasses are also light filters. Amber or yellow in fog lamps and shooting glasses give us the impression of increasing contrast.

But how the color of light appears to oncoming traffic and how effective the light is for illumination are two completely different things. To mimic a bluish HID look will diminish the amount of light used for illumination. I'd never use a bluish tinted halogen light for use in headlamps just because it may look like HID.

I'm interested in what you come up with.
I'd like some filters for 6 1/8 round 165watt KC's.
Diffusers, colored filters, maybe a yellow fog filter that's blacked out on the top half.

.

 

[landtank]

Well Doug with my limited training on the subject my understanding is that a filter just filters out a frequency range measured in Nm. The problem with most filters is that they are not very tight in the range that they are filtering so they tend to effect a wider range and have an adverse effect in areas that would ideally be left alone.

On the high end scanners that I onced serviced, the idea was to illuminate the work with as white a light as possible and then place the appropriate filter in front of the CCD (eye) and then record the image. Basically the more accurate the filter material the more expensive the scanner and the better the results.

So yes, I think your understanding is correct if I'm understanding you correctly.

 

[Safado]

I think you're fine Doug...I've seen several light packages that sell lenses to change the color, and thus the use of light.

 

[cary]

I believe you are correct. The only problem is in measuring. As you know the eye is not very good, so you really need a light meter to see which has a greater loss. Multiple measurement points would be good to help minimize the effects of different parts of the light pattern emitting different levels of light.

BTW,

Blue Filters= Yuck.
Yellow Filters= easier on the eyes, and more contrast in snow and rain.

 

[fredguy]

The attached jpg shows the spectral response of some typical color filters. The TBLU filter is a blue filter with a center wavelength of 450 nm. It absorbs light above and below the dashed lines. The green, yellow, red, and infrared filters do likewise at other center wavelengths.

 

[scottm]

The goal for good fog lights is to remove high-frequency (short wavelength, blue) light, because it scatters easiest. The fine particles in our atmosphere scatter the blue out of sunlight, so the sun looks yellow and the scattered blue light arrives from horizon to horizon, serious scattering. Scattered light doesn't get from the light to the object and back to your eye in a straght line, it's what you perceive as haze. Larger particles will scatter a wider range of frequencies, fog lights don't seem to help much in snow.

For pure efficiency you'd want to only filter the blue end of the spectrum, your material might only pass a narrow range of frequencies. Of course that might look good for driving, that's kind of a 'feel' thing. The color you "see" has to do with the brightest frequency and the average frequency. An easy test of your material would be to shine a spectrum through it with a prism onto a white surface. Have part of the spectrum unfiltered to compare with the filtered part. That will show what part of the visible spectrum is filtered, roughly. You can shine a fog light through the prism to see which colors are being produced for comparison. I'll expect to see a full write-up with pictures, aren't you glad you asked?

 

[Rookie2]

... while sitting on the can taking a Beowulf

Nice..., hope you didn't forget to wipe your Junk

No pics. please.


Rookie2

 

[Tooth Fairy]

Doug, three questions.

1. Can you make them interchangeable/reusable? I'm guessing no.

2. How heat resistant is the film?

3. You know that ID state law says no blue lights except on police vehicles, right?




Many of the light manufacturers run a tinted lens and not the bulb. Sounds like a great idea to me.

 

[ginericLC]

Doug,

I'm definitely interested in your stuff. Is it hard to work with? I mean could I install a clear hoodshield myself. My 94 had a bug deflector until recently and it is pristine. I'd like to keep it like that.

Butch,

I think the blue effect would be so faint that you wouldn't run into problems with law enforcement. Although I'm the guy who had to put his flares back on due to local law enforcement, so who knows? I think the amber would suit my needs more. Snow is what I'd want the aux. lights for. We don't have much fog. I've found that blue sucks in snow and fog.

My rock lights are blue coated and yellow coated. The yellow ones appear to be brighter at night even though the wattage is the same.

 

[photogod]

" And the blue film also shifts the normal yellowish bulbs to a clean white you'll immediately notice if that's your thing (it's not mine)."

Blue is the complimentary color to yellow so if you add blue filters to yellow light the blue cancles out the yellow making it look more white. Magenta cancles green and Cyan cancles red and vise versa. It has to do with Kalvin temp which is how the color of light is measured. The higher the K temp the whiter the light. Incandescant bulbs in your home are about 2800 to 3000 K. daylight bulbs or camera flases are roughly 5000 to 5500 K. So if you have a halogen bulb at 3000K and add a blue filter that might be 7000K you get a light from said bulb that might be close to 5000K which is considered a "daylight" type of illumination.

 

[IdahoDoug]

The clear bras are available for consumer installation. Having done close to 900 installations, I can say that I would not recommend someone trying it, even if you've had experience with a similar item like window tinting. There are so many variables its amazing, and getting a smooth install is quite difficult. Headlights are a different story - especially the 80 headlights as they're flat.

The blue headlight film I'm testing is very, very faint. You'll notice it if you're into lights and such, but an average person would not even notice it.

Thanks for the continued information on frequencies, etc. Keep it coming. I don't have a prizm, but can see how that's going to work.

I'm also doing an interesting test side by side, mentioned above with the yellow film vs a Hella Yellow Star. There is no question the film is superior if you're really looking to use yellow fogs in their best application - severely limited visibility. Here's why. Against a wall, the bulb's stray light scatter is white above and below the intended pattern of a yellow band. I don't know why the bulb was designed this way, rather than coating it yellow so ALL the light is yellow. The reason this is bad is that the whole intention of fogs cutoff beam is to prevent upward light beams, which create backflash at the driver. Yellow minimizes the backflash. But the Yellow Stars create white upward scatter and yellow in the pattern. Now stay with me here. The negative of yellow is that it reduces output down the road where the pattern is. So, the Yellow Star puts the yellow where it's least desirable (down the road) and the white where it's least desirable. Strange, but true. I cannot believe they sell these things. Ironically, it would seem to me they'd have a hell of a marketing strategy if they moved the coated areas on the bulb so the scatter was yellow and the beam pattern was white, ya know? FYI, these are in Hella's high grade 200FF fogs with the free form reflectors.

By comparison, the yellow fog film has the same yellow output on a wall to the eye, regarding color and shape, but its scatter has all been turned yellow. So, I'd rather be driving behind the film.

DougM

 

[Beowulf]

>> while sitting on the can taking a Beowulf <<

You'll pay for that smart a$$ remark. In due time my friend, in due time.

-B-

 

[PHAEDRUS]

Doug,
this is interesting for sure.
I have installed 3 or 4 of the clear bra films by 3m and your right they are a nightmare to get right. one other point on headlamps in specific is to be careful of the ford and gm cars headlamps. they have those oh so cute points that jut out so you can use a headlamp aimer to level the pattern out. havent looked at my truck to see if the toys have the points but I would think that would be a biatch with that film.
FWIW, the clear 3m 4 mil thick film works well as a rock chip reducer in the frear and front dog legs of passenger cars. just as an added point to sell to people that is easier than a hood to install on.
Dave

 

[scottm]

>> while sitting on the can taking a Beowulf <<

You'll pay for that smart a$$ remark. In due time my friend, in due time.

-B-

I guess all those years we had him in charm school were a waste!

That's wierd they only half-coated the bulbs. Any low-freq light anywhere will refract in every direction, that's what's bad about it. 'Blue Bends Best' was the memory aid in Optical Physics class. Piaa used to make a half-coated bulb for their high-low two-filament bulb, that made sense, although I never tried one. It sounds like your yellow cover is better. Not going to try the prism? It would be great for the kids, don't be neglecting my niece and nephew over there! Bring some yellow film when you come out, I'd like to play with it, maybe I can get it in a spectrum analyzer for a printout. Or where can I get a prism? Edmunds?

 

[ginericLC]

The clear bras are available for consumer installation. Having done close to 900 installations, I can say that I would not recommend someone trying it, even if you've had experience with a similar item like window tinting. There are so many variables its amazing, and getting a smooth install is quite difficult. Headlights are a different story - especially the 80 headlights as they're flat.



DougM

OK two more dumb questions then. How much and when are your travels bringing you to the Boise area? All of my headlights are protected already, but after you play with this yellow film a bit more I wouldn't mind trying some of that on the Hellas.

 

[IdahoDoug]

Scott,

Actually, there was no visible coating on the bulb at first glance. I could see something was slightly different about it, but it's not what you'd expect. I've used PIAA's Ion Crystal bulbs and they had obvious tinting layers. This is different and at first I thought it was mis labeled. I had some other bulbs shipped for the Subaru and these were only $5 so I thought I'd pick one up to check out.

Beo - too late. There's a 48hr "insult expiration clause" on the forum.

Dave,

Yes, those aiming points are a pain. I rarely come across them as we do 99% new cars, mostly imports with "real" lights. The points are handled with precut headlight kits, or a leather punch in a pinch. As for doglegs, we upsell the stuff everywhere - A pillars, doglegs, roof, etc. We prefer working with the thicker 8 mil 3M for everything except headlamps where we use the 14 mil. The colored film is not a 3M product, so I'm doing my own testing of it to see how it holds up. As an interesting side note, we demonstrate the effectiveness of the 3M film by shooting it with a 12ga shotgun and #6 steel pellets. 3M heard about them, and now I'm selling these little demonstration plates to them. Ironic, eh?

Eric,

I literally never go to Boise. Not for any reason other than the distance and that it's not on the way to anywhere we travel - geographic black hole. Heading to California, we even have 3 different routes and none through Boise. So, plan a vacation in British Columbia and stop here on your way through. I'll update with the yellow film. Putting some blue on the other fog tonight. The smoke film I don't think I'll put on a headlamp, but it would make for an interesting smoked effect on a taillamp or front blinker.

DougM