Brake Light Wavelength?

It depends upon the filter characteristics of the red translucent cover through which the tungsten emission spectrum passes, more than anything else.

If in doubt, a measurement would establish it.

My steel tape measure has light wavelength marks on it but my eyes are so bad I can't read them.

Can you find the info on that,(which was my original question?).

Declined.

Here's a specially blown one:

Hello,

It's not a wavelength as such, but a particular defined range of chromaticity and the C1931 diagram that shows the acceptable ranges for each colour. You would find the details in the older specifications of the SAE handbooks that are now public information.

Try SAE J578 and see what you get.

The Australian standards are slightly different.

I used to be signatory to the Aus equivalent to a NIST lab for optics and photometry and we did supply lamps to the US market for a while.

Probably ~650 - 680nm...

No far red then.(700-780nM)

Of course I am looking for a cheap source for far red light source.

I bought one of those off Ebay....it's incredibly bright....

Puts a red spotlight on the ceiling....these are 660nm and about $24 with lens and driver as discussed on a previous thread...

For a few bucks, you can get one of these. It would give you an idea of the spectrum of various light sources.

EISCO Premium Quantitative Spectroscope, +/- 5nm Accuracy

https://www.amazon.com/EISCO-Premium-Quantitative-Spectroscope-Accuracy/dp/B00B84DGDA/ref=sr_1_3?dchild=1&keywords=spectrascope&qid=1602526459&sr=8-3

Wow! At that price, you haven't got much to lose! Great find!

One has to use red lamp oil for these:

https://www.ebay.co.uk/itm/Railway-Train-Tail-Paraffin-Oil-Lamp-BR-W/333733334532?hash=item4db40e8e04:g:-LcAAOSwCU9fbgbY

Coming toward you or away from you,... Blue shift or red shift?

Stationary,relatively speaking.

I can't find a spectrum for a brake light, but I can find a brake light for a Spectrum...

https://www.autozone.com/electrical-and-lighting/brake-light-mini-bulb/chevrolet/spectrum

Lol,... I knew a guy like that, he was sent out on an errand with a list of things to get... it didn’t turn out well. You aren’t that guy,... are you?

Ok without reading everything else, there is no answer for this question. Tail light lenses were all different colors of red depending on the plastic and the dye used. Then there were the Red laquered bulbs behind clear lenses. Lets not forget the over kill, red bulbs behind red plastic. Oh, and those wonderful Blue Dots. How old are you?

I doubt when the standard was made that anyone really cared "what color" red it was.

I really don't care,except that I am looking for that elusive "far red" color in a common source.

I would expect looking at a very red sunset could have some benefit.

Maybe I should move to Amarillo,Texas;Most beautiful sunsets I have ever seen.

Hello,

You are mistaken about them caring what colour red it was. The Society of Automotive Engineers specifications were rather difficult to achieve. What you see now with multiple colours available is the "built to a cost" outcome that the US automotive industry accepted.

Pigment quality and durability in sunlight exposure (fading) were the first to go, quickly followed by the plastic material durability. Our business integrity shut us out of the supply chain since we didn't compromise from the "first article" expectation but other suppliers (including internal to the vehicle builders themselves) would very quickly substitute an "equivalent" but significantly cheaper material for the lenses since the vehicle owner wasn't likely to notice/care/complain about the fade 3 years into ownership.

Then came "homologation" where each country accepted the imported vehicle specification on a tit-for-tat agreement, so now we all get whatever might be accepted anywhere in the world.

Sound like a lot of arguments. Now I can go to Autozone and by a roll of red tape and I'm good to go. LoL

I agree with you.

Quality is now job None.Save $.01 cent per part is more important than durability and quality.Gotta have that quarterly return...dam the repeat customers.

Headlights should still be made from glass,that did not fade or yellow.The insignificant weight savings on the increase in mileage is laughable.

If more attention was payed to engine technology, cars should be getting twice the MPG that they do now.With all of the advances in technology,the MPG is not significantly better than in the '60's. An opposed-piston engine,where pistons travel towards each other is a good example of very old technology that is very efficient,but this tech has a hard time breaking into an established marketplace.

As far as vehicle mileage, ill resist the rant and pass an observation.

When gas mileage became topical around the world, the US automakers convinced the legislation that the efficiency should be "ton-miles per gallon", thus a vehicle that weighted 2 ton and got 12mpg got a measure of 24, while another vehicle of 1 ton that got 20mpg was perceived to be less efficient. The builders were rewarded for R&D in this area to "increase efficiency".

The 1 ton vehicle might have been less efficient at moving tons of vehicle around, but was far more efficient at moving people around. Hence the evolution from F150 to F250 to F350 and so on. (We used to manufacture the outrigger mirrors here in Aus) Similar happened in the other vehicle builders I just don't remember the model sequences.

From this side of the ocean it was interesting to be an observer of that evolution.

I want to see your tape measure.

Does anyone know of sunglasses or goggles that allow only far-red light through,or even a high percentage or far red?

It's been many years, but I believe I used to have a set of gas-welding goggles that had dark red lenses. I have no knowledge of the pass spectrum.

I now have a set of goggles intended to improve viewing of HeNe laser spots, but they are bright red, not far red.

What you want are blue blockers....I have a couple of pair....expensive and cheap, work about the same...

Cheapest....these double as safety glasses ...about $20

I have found a source for a red LED with 650-670nM wave length,but it is physically much too small for me to work with.The dimensions are 3.17mm X 4.61 mm.The part number is LXM-PD01.Data sheets available from several suppliers.If anyone has the ability to assemble these into a standard LED Flashlight,this is a lucrative market opportunity.

Just $10....

What wavelength?

In the range of 660nm....

Can you please supply a link to purchase these lights?

THANKS!

Already did, just click on the flashlight....

Those el cheapo meters are only 5um +/- so not very accurate....easier and free just type in the wavelength to a color generator and match the color of the light reflecting off a white sheet of paper...

https://academo.org/demos/wavelength-to-colour-relationship/

https://turbofuture.com/graphic-design-video/Shades-Red-Greensleeves

https://www.amazon.com/EISCO-Premium-Quantitative-Spectroscope-Accuracy/dp/B00B84DGDA/ref=sr_1_3?dchild=1&keywords=spectrascope&qid=1602526459&sr=8-3