Lumens vs Kelvin in light-Read only if you are bored out of your gourd

[Wallkeeper]

I have seen posts here and elsewhere with some confusion between what are Lumens and what does Kelvin mean...so here goes

Lumens-a measure of the total quantity of visible light emitted by a source per unit of time. If you are really bored, ANSI has very detailed discussion of how it is measured. Note that the spectral curve (color) of the light source is not a component of the measurement.

I shamelessly lifted the following from Wikipedia.....I could not have been more concise

Kelvin " kelvin is often used as a measure of the color temperature of light sources. 5600K is an arbitrary standard for Daylight aka "D56" Typically the cooler the number, the more red the color appears and the higher the number the bluer. On average, the human eye has the best color discrimination with a 4800K light source.

The difference is significant when you are buying lights and looking at different emitter types.

Stay Safe
Wally

 

[SHUMBA]

I have seen posts here and elsewhere with some confusion between what are Lumens and what does Kelvin mean...so here goes

Lumens-a measure of the total quantity of visible light emitted by a source per unit of time. If you are really bored, ANSI has very detailed discussion of how it is measured. Note that the spectral curve (color) of the light source is not a component of the measurement.

I shamelessly lifted the following from Wikipedia.....I could not have been more concise

Kelvin " kelvin is often used as a measure of the color temperature of light sources. 5600K is an arbitrary standard for Daylight aka "D56" Typically the cooler the number, the more red the color appears and the higher the number the bluer. On average, the human eye has the best color discrimination with a 4800K light source.

The difference is significant when you are buying lights and looking at different emitter types.

Stay Safe
Wally

Yup, I think we are all a little bored. So thanks for the 101 about lumens and Kelvin. I'm not sure what the Tenere's OEM lights are rated at, but in my opinion, they are inadequate. For additional visibility, along with safety, I added three LED lights on the front of the bike. It gives the bike a profile, and makes it more visible to the cagers. These three lights are controlled by a separate switch as they are far too bright for use in darkness when either meeting or following traffic. In addition they light up the ditches extremely well to detect animals. Even in the daylight I have had some cagers flash their brights at me..I just ignore them as it is not an offense to have bright lights on one's motorcycle.
Just below the headlights I have a 2,700 lumen strip light and mounted on each crash bar is a 3,450 lumen light. All lights added are very white and bright LEDs.
Bikes built today should have to come with LEDs in a triangular pattern. So I have added a total of 9,650 lumens.
SHUMBA



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[EricV]

It's an easy topic to get confused about. And often different manufacturers use different methods of measurement, mostly to prevent buyers from making apples to apples comparisons between brands or lights.

Kelvin is useful in choosing your lighting in many ways. While 5500K-6000K might be "Vertical Daylight", 5000K is considered "Horizon daylight". Mixing higher K lights with lower K lights can have the effect of increasing contrast. The trends in auto lighting has been to go to higher K light colors and people sometimes want everything to look the same from a visual standpoint, but that's not always the best in terms of results the human eye can use. Wiki

Bulb availability in HID lighting used to jump from 4300K to 5000K and up. 4300K was the most natural to the human eye and gave very good contrast. 5000K and up goes from very white to bluer as you increase the color temp. Everyone has a preference. I like to mix 'warmer' and 'cooler' temp lights for maximum contrast over med to long range lighting.

Lumens offer a useful measurement of how much light the human eye can see from a device. Lumen/Watt and other interesting stuff.

Candlepower was an attempt to give a definition to Lumens and is considered obsolete as a unit of measure.

So great, you chose your Kelvin color temperature for your lights and you hunted down the most Lumens you could afford and bolt to your bike! Awesom....

Aw crap, now we need to discuss focus and reflectors and how you get all those Lumens to where you want them to be. Never mind cut offs and not blinding every other road user down range.

Projector lights like on the Super Tenere are great at giving a sharp cut off to avoid blinding on coming drivers. And as you all learned, they suck when you lean into a corner and can't see because the light cut has almost no bleed over.

Fog pattern lights tend to have reflectors that throw light to the sides, but not out front as far as driving lights.

Ideal driving lights will push light out past your low beam focal point. Giving you more coverage in the areas you can actually use and see.

Spots punch light very far out, but in a very tight beam. However, that beam opens up as it goes out in most cases. If your spots are giving you 10' diameter circles out beyond your high beam focal point, you're getting a lot of light far enough out to ride freeway speeds or better on the darkest of nights, but you still need that mid range wide fill in between the low beam focal point and the bike so you can see the corners.

Cleat as mud, eh?

 

[Sierra1]

I know I like the hotter (6-6500) color(s). Car, bike, or house. To me, it just makes everything easier to see.

 

[EricV]

I know I like the hotter (6-6500) color(s). Car, bike, or house. To me, it just makes everything easier to see.

The higher the number K, the "cooler" the light is, which makes no sense until you think of it in terms of blue shift Vs red shift.

from the Kelvin Wiki link above.

Color temperatures over 5000 K are called "cool colors" (bluish), while lower color temperatures (2700–3000 K) are called "warm colors" (yellowish). "Warm" in this context is an analogy to radiated heat flux of traditional incandescent lighting rather than temperature. The spectral peak of warm-coloured light is closer to infrared, and most natural warm-coloured light sources emit significant infrared radiation. The fact that "warm" lighting in this sense actually has a "cooler" color temperature often leads to confusion.

 

[Alexander]

I may have caused the confusion by phrasing a post poorly, thus instigating this thread. I didn't correct it because I was just introducing myself.

The original context was, back in the day, 4300K HID headlight bulbs used to output more lumens than 6000K HID lights. (For example, from memory, a 4300K HID bulb would output around 3200 lumens, while the 6000K HID bulb would only output 2800 lumens -- despite the fact that most folks presumed 6000K was brighter). That's all I meant by the post. I was not trying to infer that the kelvin color temperature scale has anything at all to do with lumens, because it doesn't.

The kelvin color temperature scale is universal, and has more to do with how objects glow at the corresponding temperatures on the scale. Visible light is merely a form of radiation. For example, 1000K is red on the kelvin color temp scale, and if you were to heat up steel to around that temperature (1340ºF), it would glow red (steel starts to glow around 900ºF, and melts at around 2500ºF). The surface of the sun is closer to 5700K, which is why light bulbs for your house rated in that range are called "daylight" color bulbs.

There's a lot more I could say on the topic. Pretty standard physics, most schools have students measure color wavelengths/frequencies with a prism and spectrometer.

 

[Gigitt]

light colour and kelvin are also what you are able see through.

they say 5-6000K is easier on the eyes (less eye fatigue) to see things at night, shadows and depth perception are more prominent. BUT as soon as there is some kind of relefction you get blinded! also this K temp does not have penetrating power so in rain, misty and fog it created a hell of alot of glare.

fog lights are in the yellow spectrum 2800-3200K for a reason... the yellow light penetrates the rain, mist and fog giving you further vision without blinding glare.

 

[Sierra1]

Doh!! Wasn't paying attention. Was reading "warmer", but got stuck on "higher" is hotter.

 

[SHUMBA]

I may have caused the confusion by phrasing a post poorly, thus instigating this thread. I didn't correct it because I was just introducing myself.

The original context was, back in the day, 4300K HID headlight bulbs used to output more lumens than 6000K HID lights. (For example, from memory, a 4300K HID bulb would output around 3200 lumens, while the 6000K HID bulb would only output 2800 lumens -- despite the fact that most folks presumed 6000K was brighter). That's all I meant by the post. I was not trying to infer that the kelvin color temperature scale has anything at all to do with lumens, because it doesn't.

The kelvin color temperature scale is universal, and has more to do with how objects glow at the corresponding temperatures on the scale. Visible light is merely a form of radiation. For example, 1000K is red on the kelvin color temp scale, and if you were to heat up steel to around that temperature (1340ºF), it would glow red (steel starts to glow around 900ºF, and melts at around 2500ºF). The surface of the sun is closer to 5700K, which is why light bulbs for your house rated in that range are called "daylight" color bulbs.

There's a lot more I could say on the topic. Pretty standard physics, most schools have students measure color wavelengths/frequencies with a prism and spectrometer.

Thank you for your input that puts things into perspective for me.
SHUMBA

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[EricV]

light colour and kelvin are also what you are able see through.

they say 5-6000K is easier on the eyes (less eye fatigue) to see things at night, shadows and depth perception are more prominent. BUT as soon as there is some kind of relefction you get blinded! also this K temp does not have penetrating power so in rain, misty and fog it created a hell of alot of glare.

fog lights are in the yellow spectrum 2800-3200K for a reason... the yellow light penetrates the rain, mist and fog giving you further vision without blinding glare.

You did fine, say more.

 

[ballisticexchris]

Make it simple. Get a set of Baja Design lights. They do all the work to make a perfect light for any Motorsports/powersports application.

 

[Mad Earl]

I hope to offset the drawbacks of the S10's OEM lights with huge yellow halogen fog lights. Could not test them yet under real driving conditions due to virus restrictions. I found the S10's very white light detrimental in foggy conditions, and the harsh cut-off sucks when cornering.

How do you folks deal with the lights blinding oncoming traffic when you load the bike? Do you set them lower (too low then when riding alone), do you adjust them for different load conditions, or do you just live with pissed-off oncoming drivers switching to high beam to get back at you? I tried adjusting the suspension, but that does not completely offset the rear sag of the bike.

 

[ballisticexchris]

Hi there Earl, I have found that the suspension sag from various settings and loads does not effect the light height very much. I will say the OEM projection lights are a pain in the rear to get adjusted right. Low beam is too low and high beam points to the sky. I set the low beams where I want them and just use the high beams for flashing to pass.

 

[EricV]

My bike stays 'loaded' almost all the time. Clothes are what need to be packed for a trip. I leave panniers on all the time, tools, spares, etc always on the bike. For me, the difference between day ride weight and long trip weight was not very much. And I only ride solo.