Thread: ARB LED driving lights

Originally Posted by Tombie

Interestingly. The AMA has been studying the effects of High Intensity LED lighting and has begun to release some data..

This one relates to illuminating roads with "lights on a pole" however it has implications for all road lighting.

AMA Adopts Community Guidance to Reduce the Harmful Human and Environmental Effects of High Intensity Street Lighting

Interesting article. When I put the Fyrlyts on the "yellowness" of the halogen was quite apparent compared to the"whiteness" of the Discovery's Xenons. I purchased the Fyrlyts after extensive research. I was initially surprised as how "less white" they were, however, I have come to appreciate them more with use. The colour of the Fyrlyts is easy on the eye but it's true, they give much better "natural light" than HID or LED.

The ability to pick out roos, etc on the side of the road is definitely enhanced, with less blending of the wildlife into the roadside scrub. We are able to spot the wildlife much quicker even without the wildlife having to move first as seemed to be previously the case. There is greater contrast between roadside bush and a kangaroos fur at night compared to previously. The shadow cutoff is nowhere near as pronounced as with LED. I'm not talking about the edge of the light beam but simply over the irregularities of the road and verges. There is a better view of the terrain as a whole so rather than objects appearing to have sharp edges you actually see the features of the road and vegetation in far more detail.

Having extra red and yellow frequencies in the light curve of the Fyrlyts rather than the excess of blue in LED does make a difference imho.

Trevor

I hear lots of people saying 'I went to Fyrlyt from brand x/y/z in HID/LED and I'm not going back'
Never heard the opposite

Sent from my HTC One using AULRO mobile app

A few points to consider:

* the fyrlyts allow you to see more detail simply because they have either 150w or 250w globes! .. nothing to do with CRI.

* the CRI/relative intensity graphs they have on their site as 'back info' are hysterically silly.
I have no idea what he's trying to show with that, other than fyrlyts emit so mu IR(infra red), that they could be considered dangerous! remember they can be pumping out up to 500w!!

* Consider that most, if not all, sporting stadiums use massively powerful metal halide lighting. If you look at a generic metal halide spectrograph, it will look more like the warm led output, and nothing like the halogen output!
Note that when playing sports like cricket or footy under lights(eg. at the 'G') contrast is everything!

Here's a typical metal halide spectorgraph:

Now, while it's not quite exactly the same levels per wavelength, it's basic properties is more similar to the warm white LED, rather than to the dangerous IR emitting halogen!

* emitted light is not the same as reflected light!
Just because you're emitting lots of supposedly more contrasty red light, doesn't mean that light will reflect back well from the subject you're trying to see.
ie. the emissions in those graphs are in effect useless info for us humans!

So I can't fathom what it is that website is trying to explain!

As far as I can tell:
from those emission graphs, if that light is ouputting that much red and IR, then by definition it's wasting much of it's output, as humans see better in the green and blue spectrum!

I'll quote the text directly from the Wiki:

It has been established that the maximum spectral sensitivity of the human eye under daylight conditions is at a wavelength of 555nm, while at night the peak shifts to 507 nm.

from the wiki page

So why do you want red light either emitted or reflected, when our acuity levels resolve green(555nm) better during the day and bluer(507nm) better at night!
Is this not the exact opposite of what that fyrlyt website is trying to convey!!

Back to the red light emission of the spectrum:
This guy seems to think that because something is red that red light is required to see that subject?
IN the black text box in that spectorgraph area he seems to imply that because the animals in a natural environment are red/brown or whatever, that red light is needed to make them easier to see.
That's the impression I'm getting from that site.
If I have that wrong, then I apologise.
But that's not how light works.
red light in inherently very low contrast. If you don't know this, then you'll believe anything!
You've already seen it somehow somewhere, or even experienced it.
Imagine red lighting, at night .. it's easy on the eyes but it's very low powered, it allows you to view something lit up in a dark environment without losing contrast when viewing the darkness again.
And this guy wants me to believe that red light in the dark on a reddish animal is better for me to see?
if anything, the red subject is more likely to absorb the red light, rather than reflect it!

Like I said: based on the info provided on that site, those lights are something to avoid!
The better lights would be the warm white LEDs(if you're using the spectrograph to make an assessment) ..
even better for night time driving, the cool white LEDs would be the even better lights to use, as their concentrated blue/breen output isn't wasted.

Oh! and just so that you can understand where I'm coming from:
Yes I am the photographer than thinks light in photography is important, but not only for photography, driving, or reading or whatever .. it's all the same light to us!
It makes no difference for all intents and purposes, it's light, while we have nuance differences in the way we see light as individuals(ie. tastes and preferences).
Why my interest in light: I've been dabbling in UV/IR ( ultra violet/infra red, or the invisible spectrums) to see what it is we can't see.
To get a(proper) handle on it all, you need to have at least a basic understanding of light theories.
I'm in no way an expert, that much is for sure, but!!
I do know enough to know that using an emission spectrum to confirm a bunk proposition is (to put it simply) silly!

NOW!! the important part:
This doesn't imply that the lights are good. Like I said in my other post, the lights look really good, and I'm confident in my ability to predict that seeing them in person, would also impress me too.
I used to run 150w H3's in my Hella Rallye 2000's pencil beams.

sorry for the long post, but BS has to be called out for what it is, and I generally refuse to deal with companies that promote BS info.

Quote

"And this guy wants me to believe that red light in the dark on a reddish animal is better for me to see?
if anything, the red subject is more likely to absorb the red light, rather than reflect it!"

No, you are wrong and "this guy" is correct. We are talking about colour rendition at night not how our eyes react to different frequencies of the spectrum. You must remember that the colour we see from objects is the result of "colour subtraction" ( look it up). Think of it this way, during the day if you see a red car what is actually happening is that all the frequencies (colours of the rainbow simply) are striking the car from the sun. All of the frequencies are absorbed and we only see what is reflected off the object, ie not absorbed, so we see the car as red. Result is that the red car gets hot in the sun due to absorbing most frequencies of the light.

Similarly, during the day a black car gets even hotter as it absorbed virtually all light frequencies with less reflected for an observer to see. A white car essentially reflects all of the suns spectrum so we see all the frequencies, hence white light.

The colour we observe on any object is purely the result of what frequencies are reflected.

So I'm afraid you are mistaken. A red car appears red to us because the red frequency IS NOT absorbed but reflected back to our eyes, so we see it as red. At night time if you shone a blue light on a red car, virtually all of the blue light will be absorbed by the car and all you will see is a black car and you would only be able to see the car by contrast with surrounding objects. You need red frequencies to actually see the red car as they will be not absorbed but reflected so our eyes will perceive the red colour.

This is a pretty simplistic example but the principle holds true. Obviously, the more of the spectrum that the emitted light contains the more the combination of frequencies will be reflected so we will see the car in its true "daylight" colour.

A night, with animals it's no different. Lets assume a red kangaroo sitting in green bushes (yes I know this is simplistic). If you shone a blue light on these objects thay will all appear as shades of grey or dark with no or little colour reflected of the objects. They would tend to be high contrast but no colour differentiation so it would be hard to pick out the roo from the bush unless there was movement. If you added red light, the bush would still be blackish as it absorbs both blue and red, however, the roo would now show up as red as this frequency is not absorbed by the roo but reflected. You have to use some logic, if a colour frequency is absorbed by an object then how could your eyes see that colour?

In conclusion, if a driving light has more of all the colour spectrum in its emitted light then it follows that any object that that light impacts on will absorb whatever frequencies it needs and reflect back to our eyes the non absorbed frequencies. To see a red kangaroo at night, you need white light that impacts the roo and reflects back to your eyes the red frequencies so we see it as red. If it absorbed the red frequencies how would you see it as red as there would be no red light frequencies impacting your eyes? This is what Fyrlyt claim in that they state their emitted light mimics daylight better than what LED's can do. If that's the case then Fyrlyts will give a truer colour rendering at night compared to LED, independent of perceived brightness or power.

Read up on "Colour Addition" and "Colour Subtraction"

Trevor

LOL!
So if we take this to a more extreme situation, and we have a red rood against a red bush, and we shine a red coloured spot light on it, .. you're theory says that we'll differentiate the roo from the bushes more clearly!

I'd love to see that tested in the real world!

My experiments, although in a closed environment and mainly focused(pun intended) on photography, show the exact opposite effect.

A whiter/bluer light on a red on red subject is much easier to see with a cool white LED.

Colour subtraction is relevant in the sense that for a full spectrum capable device(which our eye's are definitely NOT!) makes sense(ie. UV/IR photography with the correct camera sensor).

You're confusing theory with reality.
Our eyes are capable in a limited bandwidth, and red is where the bandwidth cuts off. So as the light becomes more red, we see less of it.
Also, our eyes are more sensitive to green(as stated above, 555nm) tending to more blue wavelengths(507nm) at night, so those reflected frequencies overwhelm our ability to see red light.
This is why whiter light allows us to see better at night.

And you're trying to tell us that all those high priced luxury car makers are spending millions of dollars in researching better lights on their cars and making them more red?
.. are you serious?
Check any new high end Merc/BMW?/whatever and they're lights are all graduating to a deeper blue colour level, with every generation.
And all those manufacturers are going the wrong way?
I hardly think so.

What makes those fyrlyts impressive is one simple fact .. they're power output .. simple as that! 2x 150w or 250w is put simply a ship load of power(just like those metal halide MCG lights are).

Red light by it's physical property is a low contrast lighting effect, both in how we see it in reality and it's very wavelength property.
Some of the trucks I drive have nightime interior lights for this exact purpose.
I can drive with the (red) night lights on very barely see the controls in the truck, and just barley make out (say) a map or something, but reading fine detail is extremely difficult.
When they give me my load sheet and it's the pink type, it's nigh on impossible to read under those red night running lights, even with my glasses on.
But the white and blue run sheets are easy enough for me to read(without my cheapo $2 glasses).
This is a completely contrary experience to the theoretical info you've provided.
Reason why is simply that our eyes are not full spectrum!
That is, we(humans) can't clearly see red light, irrespective of whether it's emitted or reflected, added or subtracted!

Lower wavelengths (white to blue to UV) allow more fine detail to be captured as the fine detail becomes smaller and smaller.
While that is an extreme situation, and very relevant in full spectrum photography, the theory still extends to the real world of human visibility as well.

"So if we take this to a more extreme situation, and we have a red rood [sic] against a red bush, and we shine a red coloured spot light on it, .. you're theory says that we'll differentiate the roo from the bushes more clearly!"

You are being silly here. I didn't say anything like that.

In this simplistic example that you gave, with understanding colour subtraction, what would happen is:

Firstly the bush is green and the roo is red, (that's how it normally works). If a red spot light was shone on both the roo would not absorb the red light but reflect it, so we would see it as red. The bush would absorb the red frequencies and there would be nothing to reflect so we would see it as "black". I make no comment about how bright this would be or how our eyes would perceive the brightness in terms of the frequencies that our eyes perceive. I am purely talking about colour rendition.

In order to see reddish objects at night in their true colour we need to have red light in the emitted light in order to have them reflect red light back to our eyes. This was my initial point. It is basic physics.

In general, a 150w LED light and a 150w fyrlyt side by side, the LED will probably seem brighter due to the higher amount of blue light emitted. However, most objects in our environment that we want to look at, at night with driving lights are green (bush) and "brownish/reddish" (animals). With an LED light these object may seem "brighter" but there will be less colour contrast. To see red animals "as reddish" you need to have red right in the emitted light. This was my original point which you seem to not understand.

Obviously, there is a lot more to how good a light is and a lot is subjective.

Quote:
"This is why whiter light allows us to see better at night."

Here you must mean that a light that contains more blue in it's emitted spectrum is "whiter" at night, such as Xenon or LED. What you are really saying is that they seem "brighter" as our eyes are more sensitive to blue frequencies.

In reality, true white light is "sunlight" and this contains all the spectrum. For any driving light to be truly "white" the aim would be to mimic sunlight, would it not? The more any driving light attempts to mimic the suns frequency output the better it will be in rendering true colour in what is reflected to our eyes.

Many car manufacturers are going to Xenon, Hid, LED as you suggest. There are lots of reasons for this, but to imply that just because they have done this it makes it better to distinguish red roos from green bush in Australia is naive. If these lights have less red light in their emitted spectrum it will make it harder to see anything that is "reddish" in it's true colour.

Let's imagine for a second as a "thought experiment" the the orange colour Sodium Vapour lamps that have been used as street lamps. Lets assume for the sake of the experiment that these lights were really, really bright and car manufacturers started installed these lamps as car head lamps. Whilst, they might appear bright,the colour rendition of the reflected light back to our eyes would be terrible as what is being emitted is a limited range of the "daylight" spectrum. Similarly, Xenon, LED lights being installed now in many cars, do often appear brighter to our eyes but as they lack red light in their emitted spectrum there will be no red light reflected from objects as there is no red light available from the light source in the first place. pretty simple.

It's not all about "brightness".

Some interesting argument`s here
As has been quoted the Led technology is not there yet for distance but is a still a very good bright light depending on the quality which is major concern
My self i have 70 w Hid IPF spot beam driving light`s and a 42" light bar
The driving lights take care of the distance and the light bar takes care of the side of the road and that does it for me .

That it may be - and it's also damaging your eyes!