Best Color Temp for Eye to See the Road?

[LoneRanger]

LED's and HID's are all the rage these days, but is that ultra white light actually the best at letting your eye and brain, working together, see and interpret as much of what is out in front of you as is possible... to pick out as much detail and etc as possible? Curious based on personal experience. Through most of 2016 I had a motorcycle with LED lo and high beams, Ducati. They were well setup with good cutoff and throw but there was always a feeling of... I don't know... weirdness or something as far as how it actually lit the road and road shoulder area. Prior to that bike I'd had a earlier model Duc with LED lo beams but halogen high's. Flicking on the high beams always seemed to impart some manner of "relief" for my vision for lack of a better term. Now I've got an old school bike with dual side by side halogen headlights. While it's not as eye catching to oncomers in traffic it seems like I can actually discern the night road and road shoulder better than before. Some of this could be due to my age 54, because our night vision acuity and contrast discernment decreases with age. Also on a bike, the sag i.e. how the bike sits is relevant to head light aim and for this comparison all bikes' suspensions were dialed in okay. This has to be due to the color temp differences.

 

[PiperOne]

In the last year or so I started to switch things over to LED..and a color temp between 5000K and 6000K. I'll never go back to halogens as I find the whiter light easier to see things with. Given the multitude of color temp options I think it's a big personal preference thing. I have a neighbor who swears by lights that are pretty much yellow (to me).

 

[4WD]

Last night was the first 2 hour road trip I have taken at night in a good while … an endless parade of miss matched bulbs and reflectors did not make the trip safer for me with my OEM lights … Go on the internet and there must be a hundred bulbs disguised as as certain number bulb - I normally don’t like new laws … but surely this is out of control …

 

[SubieRubyRoo]

I think the sweet spot is probably around 5000K for most eyes. I've driven with 4300K OEM choice, 6000K in the big, beautiful, glass-lensed housings on my old Subaru, and now 5000K in my Fusion. The 6000k is super bright but can wash out some details... and the same thing with the 4300K (for my eyes). The Fusion so far is probably my favorite, but the best test would obviously be to use different bulbs in the same projector. The deeper blues, in addition to not putting out as much light per watt, are worse because of the reflectivity of their wavelengths. It will alter the way your eye can pick out things when combining the darkness and weird scatter.

 

[Cujet]

As an amateur astronomer and overall technical nerd, I've been fascinated with light forever. I wish I could answer your question with a simple "the OEM 3400K is best" statement. As I am sure you know, there are other aspects to the light produced. Including the ability to illuminate a wet black road. CRI (color rendition index) is often used to indicated which bulbs will work well inside a home. The wide spectrum lights are, in my opinion, more pleasant to drive behind. HID bulbs somewhere in the 4000-5000K range seem to be pleasant. HID bulbs over 6000K seem to illuminate Florida's wet roads better. None of them are truly wide spectrum, and some colors won't be as bright. The various flavor LED's are similar, some with fairly narrow spectrum light. The good ones are fantastic. The crummy ones have the same issues as a typical HID. When it comes down to personal preference, I still like driving behind the old HIR light bulbs. Bright and warm, with a nice color temperature and a very wide spectrum of light.

 

[NGRhodes]

https://www.bikeforums.net/electronics-l...-recommend.html From a light engineer:

Quote:

Research has shown that there is a definite sensitivity shift towards shorter wavelengths as light levels decrease.

Quote:

With higher color temperature sources (bluer light), you will typically gain 10-15% greater detection distance, given the same light output and distribution

 

[SHOZ]

The bluer the light the less you can see on wet black roads. But they seem to really light up reflective signs better.

 

[Smokescreen]

Color temp isn't what you are after...its color rendition index scale. https://en.wikipedia.org/wiki/Color_rendering_index Halogen bulbs (HIR included) with clear glass achieve a perfect 100 CRI. The color temperature can vary between 3000-3500K. Halogen is the best and it is what I use in my cars. I have an LED flashlight that has CRI95+. I also have some LED flashlights that are in the CRI80 range. I also have an incandescent bulb flashlight. Side-by-side you can tell which renders colors the truest and it is still the old school incandescent bulb. My CRI95+ light is close but you can tell its off somehow.

 

[edhackett]

Originally Posted By: LoneRanger

LED's and HID's are all the rage these days, but is that ultra white light actually the best at letting your eye and brain, working together, see and interpret as much of what is out in front of you as is possible... to pick out as much detail and etc as possible?

Quote:

Blue light causes more trouble for the eye than other colors. That is because it is harder for the eye to focus blue sharply. Different wavelengths of light (i.e. different colors) have different refractive indexes as they pass through the eyeball to the retina. Our eyes can easily focus on fine details in red or green light. But our retinas can’t handle blue light very well. Blue light scatters more widely within the eye and tends to be focused in front of the retina, making it appear slightly out of focus. What we notice is a kind of halo around bright blue lights. They also seem to produce more glare. So blue light can lead to eye strain and headaches as your eye muscles strain to bring fine details into focus.

https://www.assemblymag.com/articles/91320-beware-the-blue-light Ed

 

[Linctex]

Originally Posted By: Smokescreen

Halogen bulbs (HIR included) with clear glass achieve a perfect 100 CRI. The color temperature can vary between 3000-3500K. Halogen is the best and it is what I use in my cars.

I have to agree with this. Secondly, I hate all the super bright lights that blind me from oncoming traffic at night. I'd love to take a baseball bat to them.

 

[chrly919]

I second that emotion

 

[Cujet]

Originally Posted By: Smokescreen

Color temp isn't what you are after...its color rendition index scale. https://en.wikipedia.org/wiki/Color_rendering_index Halogen bulbs (HIR included) with clear glass achieve a perfect 100 CRI. The color temperature can vary between 3000-3500K. Halogen is the best and it is what I use in my cars.

No question CRI is a big factor. I would agree that a well configured and sufficiently bright halogen setup is a pleasure to drive behind. On my old Miata, I used Motorcycle reflectors (7 inch round, glass) with high quality H4 bulbs. Truly a pleasing setup, without annoying anyone. However, I find (it's my opinion) that the 6000K HID's illuminate a wet black road better than the halogens. That would be the only case where the HID's are more pleasing, and I think, safer. Of course, the big LED light bars are so incredibly bright, they simply light up everything. Using one on a back road, with zero traffic, is an absolute joy. Poor CRI and Poor color temperature matters not in this case.

 

[Smokescreen]

Originally Posted By: Cujet

Originally Posted By: Smokescreen

Color temp isn't what you are after...its color rendition index scale. https://en.wikipedia.org/wiki/Color_rendering_index Halogen bulbs (HIR included) with clear glass achieve a perfect 100 CRI. The color temperature can vary between 3000-3500K. Halogen is the best and it is what I use in my cars.

No question CRI is a big factor. I would agree that a well configured and sufficiently bright halogen setup is a pleasure to drive behind. On my old Miata, I used Motorcycle reflectors (7 inch round, glass) with high quality H4 bulbs. Truly a pleasing setup, without annoying anyone. However, I find (it's my opinion) that the 6000K HID's illuminate a wet black road better than the halogens. That would be the only case where the HID's are more pleasing, and I think, safer. Of course, the big LED light bars are so incredibly bright, they simply light up everything. Using one on a back road, with zero traffic, is an absolute joy. Poor CRI and Poor color temperature matters not in this case.

The moment there is dust, rain, snow, fog...any type of moisture in the air, halogen takes the crown. The back-scatter of HID, LED is awful.

 

[meep]

Originally Posted By: Linctex

Originally Posted By: Smokescreen

Halogen bulbs (HIR included) with clear glass achieve a perfect 100 CRI. The color temperature can vary between 3000-3500K. Halogen is the best and it is what I use in my cars.

I have to agree with this. Secondly, I hate all the super bright lights that blind me from oncoming traffic at night. I'd love to take a baseball bat to them.

This gets my vote so far - but--- let me add this - what about using a selective amber filter to remove a portion of the blue light? It compromises CRI but also reduces blue light scatter. I personally love driving with amber (light amber, not deep amber) lamps and find less fatigue when I've tried it. -m

 

[Smokescreen]

In inclement weather I prefer a more yellow biased tint as well especially for oncoming traffic. Another problem with leaning towards selective yellow is the overall lumen intensity (lux) would be down as a result of culling some of the spectrum. For instance a normal 9006 low beam bulb would have an output of 1000 lumens (+/- 15% or whatever the allowable manufacture variance is) and by going more selective yellow, the output might only be 800 Lumens. One would have to overdrive the element past the 1000 Lumen mark just to meet the specification and compensate for reduced element life as well. Here is a good article on Selective Yellow by a man in the know, Daniel Stern: https://www.danielsternlighting.com/tech/lights/light_color/light_color.html

 

[Kamele0N]

Best is between 4150-4300K... Regarding xenon bulbs... Osram xenarc is 4150k Philips has 4300k That is in yellow/white....to white hue...

 

[eyeofthetiger]

I think a three-foot-wide, unfocused, LED light bar mounted on the roof of a truck is just about the best way to light up the road. Color doesn't matter, but green really brings out the hulk in me.

 

[eljefino]

I suspect your Ducati's lights are more of a point light source than an incandescent plus reflector setup. This would make the shadows harsher for a given amount of light.

 

[meep]

Originally Posted By: Smokescreen

Here is a good article on Selective Yellow by a man in the know, Daniel Stern: https://www.danielsternlighting.com/tech/lights/light_color/light_color.html

that was an excellent article. Thank you for posting it. -m

 

[silverbar]

Tungsten BPF in a 7" reflector is ideal for most conditions. Color is 3500K.