Coloured halogen bulbs.
No matter what colour they are tinted and no matter how much of a claim of so many % increased light any tinting of the bulb will reduce the output of the light. To change the colour of a bulb you have to block some of the light spectrum. So ignore all the claims about increased light or increased beam as its all a sham. Its all about marketing and you can twist words to say anything you like.
Legal Colours,
In the UK headlights must be of a white colour. Though you are permitted to got for as warm a colour as what is know as selective yellow. Though a few very slight tints of off white have achieved E approval. Saying that red is absolutely forbidden in a headlight, even the smallest tint of this will get you in trouble. The majority of standard cars come with a light temperature of 3200k to 4100k, Though a few do get as high as 5800k or as low as 2500k. There are next to none that fall out side this. People often think cars have a higher k bulb due to the blue halo seen in some lamps such as that found in some BMWs. This is however just due to the dichroic lense being viewed directly off its axes. All legal bulbs will be E marked. Pleas note that these E marks apply as a lamp bulb combination. So it is illegal to fit a 9004 halogen bulb to a H3 lamp or a D2R HID bulb to a H4 lamp even though both may be approved. Be warned that any modification to a lamp or bulb will render it illegal.
The disadvantage of blue light.
Governments tests found that a standard wattage blue headlamp bulb reduced the road lighting ability of a standard headlamp by 67% and increased glare for oncoming traffic by 33%. This apparent contradiction arises because of the way the human eye handles light of different colours. The short wavelength colours are very difficult for our eyes to process and focus on. Blue and violet are very difficult for the human optical system to process correctly. Blue also is a very difficult colour of light to look at if it is at all intense it stimulates the reaction we call glare.
The advantage of yellow light.
This basically taking all the disadvantages of blue away. You take the blue away from white light and you get yellow light. Yellow lamps perform significantly better especially in poor weather and are much lower in glare than white ones. For more details on how colour effects vision take a look at this independent study
http://www.lightingresearch.org/prog...01-01-0320.pdf
Light quantity and brightness.
The amount of light a bulb gives off is given in lumens. This is very different to candle power that is relevant to the brightness. The automotive standard gives a lumens rating for a given bulb class. Normally when people are talking of the equivalent wattage bulb there talking as a power of original rating. Modern Halogen and HID bulbs can reach well over that original standard. In the UK and Europe any headlight bulbs producing over 2000 lumens is subject to very strict regulation. For example such bulbs of over 2000 lumens must only be used on the road if fitted with headlamp levelling and lens cleaning systems. It is illegal to use on the road any of these high power bulbs with out fully complying with the ECE regulations. There is also an upper limit to the total intensity of all main beam lamps combined for a road car in the UK and the rest of Europe. This limit is set at 225,000 candle power. You will fined some related document information from this ECE link
http://unece.org/trans/doc/2003/wp29...GRE-50-06e.doc
Kelvin.
Kelvin is more commonly known as a temperature scale that starts from absolute zero and continues for ever. It is impossible to have a negative Kelvin value. When refereeing to light however it is referring to something totally different. Let me take this point to expel a common myth. Kelvin has absolutely nothing to do with how bright light is. Rather Kelvin refers to the colour of light given off by a theoretical black body heated to the same value. Click this link to see a good image showing how Kelvin relates to colour
http://www.freestylephoto.biz/images...rtempchart.jpg
Retrofit HID bulbs kits.
In the UK with the governments publishing of "The Road Vehicle Lighting Regulations" of 1989
these kits were made illegal to use on the public road. It is an offence to use such kits on the road. For the latest regulations visit the governments Department For Transports home page
www.dft.gov.uk And more on the European commissions website
www.unece.org According to the police the maximum fine for having these fitted to a road vehicle in the UK is £2500. Also if such a kit is found to be a factor in any incident on the road you can be held liable and end up with a limitless fine and limitless time in jail. These kits are also banned in the rest of Europe, Hong Kong, US and most of the rest of the world.
General disadvantage of HID bulbs.
A big issue with HID headlights is there significantly worse colour rendering index. HID are in the high 60s to low 70s. Halogen tends to be in the mid 90s. This means that the human eye colour perception and differentiation is massively superior under halogen light than under the light produced by automotive HID. Or simply put you can see better with a halogen light. For basic information on what the colour rendering index is all about follow this link
http://www.learn.londonmet.ac.uk/pac...rendering.html
High wattage halogen bulbs.
Lm for Lm these bulbs produce a far superior light than HID with increases visibility and reduced glare. Though they are still much like the retrofit HID bulbs, this is in that they are also illegal for road use in the UK and Europe just as retrofit HID bulbs are. Though significantly higher wattage bulbs do have an added disadvantage of they can overload the original electrical system. Though moderate increase in bulb wattage has been used for many years for off road applications on many otherwise standard variety of cars. You can be fined up to £1000 for having these fitted to a road going Saxo. Also if such a kit is found to be a factor in any incident on the road you can be held liable.
Fog lamps.
Fog lamps light the road literally right in front of you. In fog that gives you light that is not reflected directly back at your eyes and so helps visibility. There are two notable disadvantage of fog lamps. The primary disadvantage is they are not directed as headlights are and induce significant dazzle to oncoming traffic. In normal conditions the extra light directly in front will compromise your night vision and significantly reduce the distance you can see. Incidentally its also illegal to use your fog lights on the public roads on a clear night. You can be given a on the spot penalty notice or even prosecuted for doing so. If using such light incorrectly is found to be a factor in any incident on the road you can be held liable. Here is a handy link regarding the proper use of fog lights
http://www.askthe.police.uk/content/Q400.htm
Insurance.
All insurance companies cover them self from dangerous cars and intenchinaly dangerous drivers. Driving a car in not a legal manner can leave you very open, but not half as much as driving a intenchinaly illegal car. Don’t forget in the eyes of the law ignorance is not a defence.
So to sum up get uncoloured bulbs to get the most light, yellow fog light bulbs are a good idea, turn your fog lights off on a clear night and don’t fit high wattage halogens or HID bulbs to your road going Saxo.
Yes I got bored
Truth about lights.
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