Understanding the K "rating" of HID bulbs
#1
07-22-2006, 12:40 AM
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Understanding the K "rating" of HID bulbs
It is very important to understand the K rating when selecting HID bulbs. These bulbs are far too expensive to make a mistake and buy the wrong ones. And based on the bulbs that are marketed and purchased, most buyers don’t understand what they are getting.
All objects radiant energy at a wavelength which is dependent on their surface temperature. As the temperature increases, the wavelengths gets shorter and shorter.
Consider a metal like steel. When it is heated and its temperature increases, it eventually begins to glow a dull red. As the temperature continues to increase, the apparent color of the glow changes to a brighter and brighter red, then to yellow and eventually white.
The metal was really radiating energy even before it was heated, but the energy was at a wavelength that the human eye cannot see. Similarly, if it were heated above the white stage (which is not physically possible because it would boil away) it would drift towards blue light and appear to get dimmer and dimmer. This is because the wavelengths radiated at extreme temperatures (ultraviolet) again fall outside the range of the human eye.
There are thee primary temperature scales, farenheit, celcius and kelvin. They differ in zero point and in magnitude of temperature change represented by each degree. The zero point of C is the freezing point of water while the zero point of K is absolute zero (about –454F). Each degree K is the same as a degree C in magnitude. In physics, temperature is usually measured in K because it is an absolute scale.
What all this is leading to is that the color of light is directly related to the temperature of the radiating source. As the temperature increases, light moves from infrared to red to yellow to white and then blue.
HID bulbs are indentified by the kelvin (operating) temperature of the gas in the capsule producing the light. Thus, when comparing bulbs at 4300K, 6000K, 8000K, 12000K and 15000K, the light they produce becomes bluer and bluer and eventually moves towards purple. Halogen bulbs are about 3500K.
A very important related factor is that the human eye cannot process or use all wavelengths equally. Blue light is particularly difficult for the eye to focus on. This is why high end sunglasses filter out part of the blue spectrum to improve visual clarity, and the benefit is obvious.
Some people believe that HID bulbs improve or get brighter as the K temperature increases when in reality, the opposite is true. The bulbs which produce the most usable light to the eye are the 4300K bulbs. The 6000K bulbs are noticably bluer, and, as a result, make it more difficult for the eye to see. Objects illuminated by 6000K light begin to appear fuzzy or indistinct. Higher K bulbs like 8000K are worse and 12000K bulbs are almost useless for illumination because most of the energy they produce is wasted - that is it is outside the range of the human eye.
In the end, what headlights look like to other drivers is insignificant compared to how well they enable one to see where they are going. Don't choose a bulb because it looks cool.
When comparing 4300K and 6000K HID bulbs side by side, the 4300 bulbs are clearly superior. In addition, the 4300K bulbs produce more lumens of light than any of the higher K temperature HIDs.
Bottom line – if you want HID bulbs that will give the best night visibility, 4300K bulbs definitely outperform all of the higher K bulbs.
All objects radiant energy at a wavelength which is dependent on their surface temperature. As the temperature increases, the wavelengths gets shorter and shorter.
Consider a metal like steel. When it is heated and its temperature increases, it eventually begins to glow a dull red. As the temperature continues to increase, the apparent color of the glow changes to a brighter and brighter red, then to yellow and eventually white.
The metal was really radiating energy even before it was heated, but the energy was at a wavelength that the human eye cannot see. Similarly, if it were heated above the white stage (which is not physically possible because it would boil away) it would drift towards blue light and appear to get dimmer and dimmer. This is because the wavelengths radiated at extreme temperatures (ultraviolet) again fall outside the range of the human eye.
There are thee primary temperature scales, farenheit, celcius and kelvin. They differ in zero point and in magnitude of temperature change represented by each degree. The zero point of C is the freezing point of water while the zero point of K is absolute zero (about –454F). Each degree K is the same as a degree C in magnitude. In physics, temperature is usually measured in K because it is an absolute scale.
What all this is leading to is that the color of light is directly related to the temperature of the radiating source. As the temperature increases, light moves from infrared to red to yellow to white and then blue.
HID bulbs are indentified by the kelvin (operating) temperature of the gas in the capsule producing the light. Thus, when comparing bulbs at 4300K, 6000K, 8000K, 12000K and 15000K, the light they produce becomes bluer and bluer and eventually moves towards purple. Halogen bulbs are about 3500K.
A very important related factor is that the human eye cannot process or use all wavelengths equally. Blue light is particularly difficult for the eye to focus on. This is why high end sunglasses filter out part of the blue spectrum to improve visual clarity, and the benefit is obvious.
Some people believe that HID bulbs improve or get brighter as the K temperature increases when in reality, the opposite is true. The bulbs which produce the most usable light to the eye are the 4300K bulbs. The 6000K bulbs are noticably bluer, and, as a result, make it more difficult for the eye to see. Objects illuminated by 6000K light begin to appear fuzzy or indistinct. Higher K bulbs like 8000K are worse and 12000K bulbs are almost useless for illumination because most of the energy they produce is wasted - that is it is outside the range of the human eye.
In the end, what headlights look like to other drivers is insignificant compared to how well they enable one to see where they are going. Don't choose a bulb because it looks cool.
When comparing 4300K and 6000K HID bulbs side by side, the 4300 bulbs are clearly superior. In addition, the 4300K bulbs produce more lumens of light than any of the higher K temperature HIDs.
Bottom line – if you want HID bulbs that will give the best night visibility, 4300K bulbs definitely outperform all of the higher K bulbs.
#2
07-22-2006, 01:18 AM
#3
07-22-2006, 01:29 PM
But 100000K is bad azzz!
With the variance among manufacturers, anything 6000K and higher is just various shades of blue or purple with various levels of brightness. Some 8000K bulbs are blue, some are purple, depending on the maker of the bulbs.
People will always justify the purchase of their blue bulbs by saying that they're either brighter or just barely less bright compared to the OEM bulbs. You can given then the technical data on lumens straight from Philips, but they're still say that their own eyes are better guages of lumens. Or they'll cite the "data" found on the ebay page selling the Korean/Taiwanese bulbs.
Our eyes will adjust to the level of brightness. If you new aftermarket bulbs aren't as bright the pupils will dilate more. The blue shades are also more noticeable or harder on the eyes.
Here's a pic I took yesterday, it helps illustrate the idea of the eye compensating for the level of brightness.
Usually my TSX projectors are plenty bright and do a fine job of illuminating the road. The beam pattern of the the TSX projectors is partially outlined with the blue dots.
But when the TL projectors are also on, partially outlined in red, you can hardly notice the TSX beam pattern, and it appears darker than it would usually.
With the variance among manufacturers, anything 6000K and higher is just various shades of blue or purple with various levels of brightness. Some 8000K bulbs are blue, some are purple, depending on the maker of the bulbs.
People will always justify the purchase of their blue bulbs by saying that they're either brighter or just barely less bright compared to the OEM bulbs. You can given then the technical data on lumens straight from Philips, but they're still say that their own eyes are better guages of lumens. Or they'll cite the "data" found on the ebay page selling the Korean/Taiwanese bulbs.
Our eyes will adjust to the level of brightness. If you new aftermarket bulbs aren't as bright the pupils will dilate more. The blue shades are also more noticeable or harder on the eyes.
Here's a pic I took yesterday, it helps illustrate the idea of the eye compensating for the level of brightness.
Usually my TSX projectors are plenty bright and do a fine job of illuminating the road. The beam pattern of the the TSX projectors is partially outlined with the blue dots.
But when the TL projectors are also on, partially outlined in red, you can hardly notice the TSX beam pattern, and it appears darker than it would usually.
#4
07-22-2006, 01:56 PM
#5
07-22-2006, 03:54 PM
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Originally Posted by Garyv01
I have 8000K's and i love em...visibility i feel is just as good as 4300K...but i do agree with your argument that as temperature gets higher wavelengths get shorter...good example is the sun producing the most harmful and shortest rays.. Gamma Rays
#7
07-22-2006, 05:22 PM
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07-22-2006, 05:26 PM
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Originally Posted by E_K
Our eyes will adjust to the level of brightness. If you new aftermarket bulbs aren't as bright the pupils will dilate more.
The eye does in fact dialate in low light, but it is already fully dialated at light levels well above those experienced in night driving, regardless of headlights. That is, a lower level illumination from some headlight bulbs does not cause additional dialation beyond that already present simply because the eye is maxed out already.
Less usable light from higher K bulbs translates into poorer visibility, it's as simple as that. As the kelvin temperature of the bulbs increases past a true 5000K, it is just not possible to see as well.
People who buy those bulbs do it for reasons other than wanting to see as well as possible at night.
Last edited by exagorazo; 07-22-2006 at 10:04 PM.
#9
07-22-2006, 09:53 PM
I guess after you shove out 200+ dollars for some crap bulbs you have to justify it to the end. But ^ he is right, if we could see infrared and all the other wavelengths, then sure go with the 10K Kelvin one, it sure will be a rainbow on the road. But while our scientology buddies have not bring their alien friends to teach us how, STICK TO STOCK if you don't know anything about lights.
#10
07-22-2006, 11:26 PM
Registered User
Originally Posted by exagorazo
It is very important to understand the K rating when selecting HID bulbs. These bulbs are far too expensive to make a mistake and buy the wrong ones. And based on the bulbs that are marketed and purchased, most buyers don’t understand what they are getting.
All objects radiant energy at a wavelength which is dependent on their surface temperature. As the temperature increases, the wavelengths gets shorter and shorter.
Consider a metal like steel. When it is heated and its temperature increases, it eventually begins to glow a dull red. As the temperature continues to increase, the apparent color of the glow changes to a brighter and brighter red, then to yellow and eventually white.
The metal was really radiating energy even before it was heated, but the energy was at a wavelength that the human eye cannot see. Similarly, if it were heated above the white stage (which is not physically possible because it would boil away) it would drift towards blue light and appear to get dimmer and dimmer. This is because the wavelengths radiated at extreme temperatures (ultraviolet) again fall outside the range of the human eye.
There are thee primary temperature scales, farenheit, celcius and kelvin. They differ in zero point and in magnitude of temperature change represented by each degree. The zero point of C is the freezing point of water while the zero point of K is absolute zero (about –454F). Each degree K is the same as a degree C in magnitude. In physics, temperature is usually measured in K because it is an absolute scale.
What all this is leading to is that the color of light is directly related to the temperature of the radiating source. As the temperature increases, light moves from infrared to red to yellow to white and then blue.
HID bulbs are indentified by the kelvin (operating) temperature of the gas in the capsule producing the light. Thus, when comparing bulbs at 4300K, 6000K, 8000K, 12000K and 15000K, the light they produce becomes bluer and bluer and eventually moves towards purple. Halogen bulbs are about 3500K.
A very important related factor is that the human eye cannot process or use all wavelengths equally. Blue light is particularly difficult for the eye to focus on. This is why high end sunglasses filter out part of the blue spectrum to improve visual clarity, and the benefit is obvious.
Some people believe that HID bulbs improve or get brighter as the K temperature increases when in reality, the opposite is true. The bulbs which produce the most usable light to the eye are the 4300K bulbs. The 6000K bulbs are noticably bluer, and, as a result, make it more difficult for the eye to see. Objects illuminated by 6000K light begin to appear fuzzy or indistinct. Higher K bulbs like 8000K are worse and 12000K bulbs are almost useless for illumination because most of the energy they produce is wasted - that is it is outside the range of the human eye.
In the end, what headlights look like to other drivers is insignificant compared to how well they enable one to see where they are going. Don't choose a bulb because it looks cool.
When comparing 4300K and 6000K HID bulbs side by side, the 4300 bulbs are clearly superior. In addition, the 4300K bulbs produce more lumens of light than any of the higher K temperature HIDs.
Bottom line – if you want HID bulbs that will give the best night visibility, 4300K bulbs definitely outperform all of the higher K bulbs.
All objects radiant energy at a wavelength which is dependent on their surface temperature. As the temperature increases, the wavelengths gets shorter and shorter.
Consider a metal like steel. When it is heated and its temperature increases, it eventually begins to glow a dull red. As the temperature continues to increase, the apparent color of the glow changes to a brighter and brighter red, then to yellow and eventually white.
The metal was really radiating energy even before it was heated, but the energy was at a wavelength that the human eye cannot see. Similarly, if it were heated above the white stage (which is not physically possible because it would boil away) it would drift towards blue light and appear to get dimmer and dimmer. This is because the wavelengths radiated at extreme temperatures (ultraviolet) again fall outside the range of the human eye.
There are thee primary temperature scales, farenheit, celcius and kelvin. They differ in zero point and in magnitude of temperature change represented by each degree. The zero point of C is the freezing point of water while the zero point of K is absolute zero (about –454F). Each degree K is the same as a degree C in magnitude. In physics, temperature is usually measured in K because it is an absolute scale.
What all this is leading to is that the color of light is directly related to the temperature of the radiating source. As the temperature increases, light moves from infrared to red to yellow to white and then blue.
HID bulbs are indentified by the kelvin (operating) temperature of the gas in the capsule producing the light. Thus, when comparing bulbs at 4300K, 6000K, 8000K, 12000K and 15000K, the light they produce becomes bluer and bluer and eventually moves towards purple. Halogen bulbs are about 3500K.
A very important related factor is that the human eye cannot process or use all wavelengths equally. Blue light is particularly difficult for the eye to focus on. This is why high end sunglasses filter out part of the blue spectrum to improve visual clarity, and the benefit is obvious.
Some people believe that HID bulbs improve or get brighter as the K temperature increases when in reality, the opposite is true. The bulbs which produce the most usable light to the eye are the 4300K bulbs. The 6000K bulbs are noticably bluer, and, as a result, make it more difficult for the eye to see. Objects illuminated by 6000K light begin to appear fuzzy or indistinct. Higher K bulbs like 8000K are worse and 12000K bulbs are almost useless for illumination because most of the energy they produce is wasted - that is it is outside the range of the human eye.
In the end, what headlights look like to other drivers is insignificant compared to how well they enable one to see where they are going. Don't choose a bulb because it looks cool.
When comparing 4300K and 6000K HID bulbs side by side, the 4300 bulbs are clearly superior. In addition, the 4300K bulbs produce more lumens of light than any of the higher K temperature HIDs.
Bottom line – if you want HID bulbs that will give the best night visibility, 4300K bulbs definitely outperform all of the higher K bulbs.
#11
07-23-2006, 01:32 AM
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i have 30000k bulbs....i only bought them for the color...light output on the road is garbage...but i added the same kit in my fogs and also took the covers off the bulbs and reaimed my lights....now i can see better.... but 3800k is the best...yellow for visibiltiy....but i didnt change mine for better visibility jsut for looks...i like em...
#12
07-23-2006, 02:15 AM
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