Clear vs. Colored lenses for LED bars - any real difference?

[PJD642]

Other than the obvious "identification" benefits, do colored lenses really make any practical difference on LED bars, as far as how "bright" they appear? I'm building an LED Freedom-type bar, and rather than interleaving different lens colors it'd be simpler to just use clear for everything but the end caps.

 

[foxtrot5]

I don't think it make any practical difference in brightness. And if you're using clear lenses, use clear endcaps too.

 

[FSEP]

I've noticed that led light bars with colored lenses tend to have less/none split fail/purple blob... while most likely unattentional, it is a good thing.

 

[Quickstep80]

I've noticed that led light bars with colored lenses tend to have less/none split fail/purple blob...

Isn't that rather a matter of arranging the differently colored LED modules properly and choosing reasonable flash patterns?


Personally, I feel that colored lenses are mainly used for identification purposes. I'm no expert at all, but as far as I understand LED technology and basics about optics I can't find any point why there should be colored lenses over an LED module other than for "design" reasons.

 

[chief1562]

Other than the obvious "identification" benefits, do colored lenses really make any practical difference on LED bars, as far as how "bright" they appear? I'm building an LED Freedom-type bar, and rather than interleaving different lens colors it'd be simpler to just use clear for everything but the end caps.

Here' 2 examples first is a light I built with Gen 1 FS leds from a Vista normally they have a red filter in frt of them I choose not to because there wasn't room for filters.

Basicly with Gen 1 leds the reason they were meant to be put behind the red filters is that it would give a fuller color picture. if I had some left I could show you what it looks like. Have blue Gen1 that are not unpacked yet I will try and give a better picture of them with and wthout the filter when I locate them.


I'll set them up for side to side comparison. which would be better for illustration flashing or steady?

 

[FSEP]

Isn't that rather a matter of arranging the differently colored LED modules properly and choosing reasonable flash patterns?

This is where the"while most likely unattentional benefit, its a good thing" comes into play.

 

[lafd55]

I love colored lenses over LEDs. I think it gives the LEDs a deeper color and more noticeable, especially in sunny/bright situations. I would go for that, just don't put one color under a different color lens.

 

[tvsjr]

I've noticed that led light bars with colored lenses tend to have less/none split fail/purple blob... while most likely unattentional, it is a good thing.

Someone who known enough about emergency lighting and cares enough to option colored lenses rather than the default clear will likely also spend time configuring flash patterns, thinking about head/color configuration, etc.


IMO - clear lenses are great for low-profile (POV, unmarked, etc.) installs. For marked vehicles, I think it depends on the purpose... but I don't think clear lenses on a Liberty really make it all that much stealthier. Any large vehicles and basically all marked FD vehicles should have colored.

 

[EMT FIRE]

I had colored lens right beside a clear lens on my light bar and ended up taking the colored ones off. Having clear lens on my tomar heliobe made it 5 times brighter than having colored lens on it.

 

[JohnMarcson]

The color temp/output difference between colored leds under a clear lens and under a colored lens difference is imperceptible to the human eye.

 

[arsenal10]

I seem to find that in direct bright sunlight colored lenses are more noticeable. Even more so on a halogen bar, vs a clear dome with colored filters.

 

[Phoenix_Rising]

I seem to find that in direct bright sunlight colored lenses are more noticeable. Even more so on a halogen bar, vs a clear dome with colored filters.

I always figured that was because the colored lense help remove the "washout" of sunlight. But I've no scientific basis for this

 

[tvsjr]

I had colored lens right beside a clear lens on my light bar and ended up taking the colored ones off. Having clear lens on my tomar heliobe made it 5 times brighter than having colored lens on it.

A Heliobe bar (assuming you mean a 950N) is a STROBE bar... not an LED bar. The OP was specifically discussing LED bars, as mentioned in the title of this thread.


A strobe (or halogen) bar works by generating a white light, then filtering it so only certain wavelengths pass. This, by definition, reduces the output. LEDs are a pure color when generated - assuming the filter is properly colored and allows the wavelength of the generated light to pass through (relatively) unimpeded, there is no significant loss of output.

 

[SNOW SYSTEMS]

As far as being sunny out, a colored lense vs a clear lens does help, But for a cop or someone with a new 50K dollar personal vehicle a clear lens is desired, where on a fire truck, public works truck etc opt for a colored lens.

 

[nerdly_dood]

I always figured that was because the colored lense help remove the "washout" of sunlight. But I've no scientific basis for this

But you don't need a scientific basis. It just makes sense. When the sun's shining on the reflector, it's basically already glowing. Colored lenses basically act as tinted windows to cut that down so the perceived difference in brightness between the on and off states is much greater than it would be with clear lenses. The amount of light colored lenses block from the LEDs is negligible.


...All of that only matters during the daytime, and particularly when it's sunny. At night there's no difference.

 

[arsenal10]

Being color blind I also find colored lenses to be easier to distinguish between red and amber, during daytime specifically.

 

[SNOW SYSTEMS]

I believe the L31 and L32 whelen beacons is not class 1 with a clear lens where the colored domes are class 1. Just a thought

 

[PJD642]

So, we've got this:

The color temp/output difference between colored leds under a clear lens and under a colored lens difference is imperceptible to the human eye.

but then there's this:

You do lose some light output, about 7% through clear virgin polycarbonate, and 15 to almost 30% for colored polycarbonate, with blue being on the higher end of that range. Had a very interesting discussion with an engineer at one of the major lighting companies about how this impacts SAE and CA Title 13 certification at a conference a few years ago.

and of course these:

I seem to find that in direct bright sunlight colored lenses are more noticeable.

But you don't need a scientific basis. It just makes sense. When the sun's shining on the reflector, it's basically already glowing. Colored lenses basically act as tinted windows to cut that down so the perceived difference in brightness between the on and off states is much greater than it would be with clear lenses. The amount of light colored lenses block from the LEDs is negligible.

as opposed to this:

My understanding is that it is thought that the larger shift in hue from off to on with a clear lens light makes it more effective. I'm not sure how rigorously this had been studied, but I tend to agree empirically.

So...I guess I'll have to figure this one out for myself, because knowledgeable folks are telling me contrary things. Once my other flasher arrives I'll mock things up in the garage and experiment to see what I feel is "brighter" (if there is any appreciable difference), and go from there.


Jared - was (your first quote, on the reduction of light thru lenses) specifically for LEDs? Because I can certainly believe it's accurate for halogen and strobe, but by my admittedly unscientific testing methods (holding a lens in front of an LED head in a dark garage), I don't see any difference in the amount of light being thrown. Could it be that Whelen "tunes" their heads to match the lenses or vice versa, so as to allow the maximum amount of light at a certain frequency to pass? If that were true, wouldn't it then follow that the "teal" whelen heads would appear dimmer behind whelen blue lenses than the darker blue whelen heads? Has anyone noticed this?

 

[chief1562]

Being color blind I also find colored lenses to be easier to distinguish between red and amber, during daytime specifically.

You must have a problem with red & green then.

 

[pdk9]

I think the biggest factor is the layout of the lightheads and how you flash them (ie alternating the red and the blue on a RRRBBB arrangement is obviously going to produce a better footprint than randomly flickering an RBRBRB arrangement). However, all other factors being equal, I prefer colored lenses. While I don't have anything scientific to back it, IMHO you get a truer/darker color footprint during the daytime with colored lenses. Also, though it doesn't bother everyone, colored lenses tend to yellow a bit over time; it doesn't really do anything when they're on, but you notice it when the bar is off

 

[nerdly_dood]

You do lose some light output, about 7% through clear virgin polycarbonate, and 15 to almost 30% for colored polycarbonate, with blue being on the higher end of that range. Had a very interesting discussion with an engineer at one of the major lighting companies about how this impacts SAE and CA Title 13 certification at a conference a few years ago.

Are you sure this applies to LEDs, or filtered white lights like strobes and halogen?

 

[RescueWV]

I've been waiting for this sort of topic to come back up ever since I found this video. The video linked below shows a truck with three amber Federal Signal LED highlighters, two with clear lens, one with an amber one. At least in my opinion, the colored lens has more of a crisp and visible color in the sunlight. The video wasn't designed to be a comparison of colored vs. clear lens, but I think it does a really good job.

http://www.youtube.com/watch?v=JXjdEIxwmqg

 

[Sigma Safety]

... White LEDs are brighter than colors because the DOE is pouring tax dollars into their development. So much brighter that even going through a colored lens they still beat out a colored LED.

FedSig's newest generation of Pulsator and Ultrastar LED beacons use white LEDs behind a coloured dome. Very bright . I put the older Ultrastar (using amber LEDs / amber dome) beside the new one (white LEDs / amber dome) and the newer one is noticeably brighter.


The newer one's price is also about 25% lower than the older Ultrastar. Plus, now I stock 1 model of light and a bunch of spare domes of various colours. When someone walks in and wants a green or blue LED beacon, I just swap the dome out and voila. Love it.

 

[PJD642]

I've been waiting for this sort of topic to come back up ever since I found this video. The video linked below shows a truck with three amber Federal Signal LED highlighters, two with clear lens, one with an amber one. At least in my opinion, the colored lens has more of a crisp and visible color in the sunlight. The video wasn't designed to be a comparison of colored vs. clear lens, but I think it does a really good job.

I gotta say, the light with colored lens does seem to stand out better and be more noticeable when flashing.

 

[JohnMarcson]

Even more so on a halogen bar, vs a clear dome with colored filters.

apples and oranges....

I gotta say, the light with colored lens does seem to stand out better and be more noticeable when flashing.

Often I suspect this is not the lens color, but the fact that bars with colored lenses tend to group the colors together.

I've been waiting for this sort of topic to come back up ever since I found this video. The video linked below shows a truck with three amber Federal Signal LED highlighters, two with clear lens, one with an amber one. At least in my opinion, the colored lens has more of a crisp and visible color in the sunlight. The video wasn't designed to be a comparison of colored vs. clear lens, but I think it does a really good job.

http://www.youtube.com/watch?v=JXjdEIxwmqg

The color (on camera) certainly does appear more true. That would be the benefit of colored lenses I suppose, cleaning up the color. After all lightbar lenses are actually just filters.

 

[Sigma Safety]

I gotta say, the light with colored lens does seem to stand out better and be more noticeable when flashing.

I tend to agree. I think it's actually the contrast. With a coloured lens, it's darker than a clear lens, so you get better off-to-on contrast so it's more attention getting. With a clear dome, it is fairly bright just sitting there in the sun, so when you turn on the LEDs it doesn't get that much brighter.... if that makes sense. It's really the off-to-on contrast ratio that makes the difference.


I'm not a fan of these clear brake light lenses that are popping up everywhere. I find that the bulbs (or LEDs) behind a red lens tend to grab my attention better - I think it's because of the contrast.

 

[Quickstep80]

Never ever take a video as evidence for topics like this. Especially when it's apparently some footage that was recorded with a consumer camcorder and "default/automatic" settings.


Since I'm running a film company myself, I just want to underline that such pictures never ever do justice to reality in terms of real colors, brightness, contrast and much more. It would take huge efforts to record a scene "correctly" and again much time in postproduction to still work on some aspects.


So never trust a camcorder, especially when recording with automated settings or changing position while videotaping without selecting new proper parameters.

 

[RescueWV]

Can we get a video with the domes off? Are those all Amber LEDs or are the center ones White?

-Jared

It's not my video, just something I found while looking for videos of Highlighter LEDs. I can only assume that all of the LEDs are in fact amber, because I've never seen a Federal Signal bar with white LEDs under a colored dome.


I realize that this video is by no means scientific, and is in fact anecdotal at best. I just posted it to show that at least in this particular case of side-by-side comparison, it seems to make a difference.

 

[nerdly_dood]

It's not my video, just something I found while looking for videos of Highlighter LEDs. I can only assume that all of the LEDs are in fact amber, because I've never seen a Federal Signal bar with white LEDs under a colored dome.

I think that's what they did for the purple Highlighter LED, at least while they had it.

 

[rwo978]

http://elightbars.org/forums/f13/light-emitting-diode-terms-101-colors-1163/

 

[Sigma Safety]

It's not my video, just something I found while looking for videos of Highlighter LEDs. I can only assume that all of the LEDs are in fact amber, because I've never seen a Federal Signal bar with white LEDs under a colored dome.....

I'm fairly certain that only the Pulsator LED beacon and the new Ultrastar LED beacon use the white LEDs and the coloured domes. None of the lightbars do, to my knowledge, nor the mini-bars.


These new whites are outrageously bright. The Pulsator uses 3 LEDs and meets Class 1 even with an amber dome over the white LEDs. The Ultrastar uses a whopping 6 (6 vonderful LEDs! Heh Heh) LEDs and is even brighter than the Pulsator.

 

[Black Hoe]

To the OP, I have always preferred the appearance of colored lenses for LED light bars. The colors just look more richer or vivid when illuminated and when off, the vehicle just looks more official.

 

[FSEP]

For those of you with more knowledge on this then me (not hard), what if any light output is lost by using colored lenses with the same color LEDs behind them?


On a side note, with rotators, how dark (percentage) is the lens on the light in order for the white light to turn the "normal shade" of the new color?

 

[Sigma Safety]

For those of you with more knowledge on this then me (not hard), what if any light output is lost by using colored lenses with the same color LEDs behind them?

On a side note, with rotators, how dark (percentage) is the lens on the light in order for the white light to turn the "normal shade" of the new color?

With LEDs, the coloured lens over them doesn't really affect the light output a whole lot. It does a bit, but the human eye can't detect it. If you have blue light, which normally has a wavelength of about 450nm, you tune the blue dome/lens to allow 450nm through, so theoretically there is zero loss if you can exactly match your dome tint to the LED colour. However, LEDs shift colour a bit once they warm up, so as they shift, they can move to 430nm or something (just a guess) so it won't go through the 450nm filter as well, so it loses some power. The SAE tests for colour specify that the LED has to be on for 20 minutes before it is tested for colour - that's specifically for the colour-shift issue. Also, lens tinting isn't an exact science - the tint can vary a tiny bit between batches which can mess with the LED/filter colour matching. However, for all of that, you will barely detect it with your eye (likely you won't be able to detect it at all) but it does matter to the optical instruments that measure such things for SAE compliance, etc.


With a clear lens, you don't get the issue of the colour-shifted LED falling out of the 450nm filter , because the clear dome will let all colours pass through, so no matter how much your LED colour shifts, it'll still get through. I suspect that's why you see some manufacturers have LED beacons that meet Class 1 when using a clear dome, but they only meet Class 2 with a coloured dome (even though in both cases they use the same amber LEDs).


Of course, all of the above is out the window when you use white LEDs behind a coloured dome


With halogens, it's a completely different issue. Halogen lights emit full spectrum light over the entire wavelength spectrum, then we use a filter to block everything except 450nm (in the case of blue) through. That means that 90%+ of the light is blocked by the filter and is wasted. The amount of tint in the dome/lens depends on a number of factors including the colour desired, the power of the bulb, etc.

 

[FSEP]

Thank you! That's a lot of info and it was really helpful. :thumbsup:


I do have one last question though... Can you explain the bottom a little more? The reason I ask is because I'm about to pick up some white led dashlights, but I have some blue tint in the way of where I want to place them. I'm sure the blue tint will diminish the amount of white and make it look blue, however to what extent I'm unsure. I never thought about testing it before when I had other dashlights. lol

Of course, all of the above is out the window when you use white LEDs behind a coloured dome

 

[Sigma Safety]

Thank you! That's a lot of info and it was really helpful. :thumbsup:

I do have one last question though... Can you explain the bottom a little more? The reason I ask is because I'm about to pick up some white led dashlights, but I have some blue tint in the way of where I want to place them. I'm sure the blue tint will diminish the amount of white and make it look blue, however to what extent I'm unsure. I never thought about testing it before when I had other dashlights. lol

You'll just need to try it, really, and see if it looks like the correct colour of blue. I can't suggest any rocket science for that setup - just give it a try.