Are Blue Coated Headlight Bulbs Road Legal? What Is the Best Bulb for Me?

Are Blue Coated Headlight Bulbs Road Legal? What Is the Best Bulb for Me?

When it comes to car ‘styling’ headlight bulbs, there can be a lot of confusion around the legality of blue coated halogen bulbs. We are really shocked when we read some information other companies present on their websites and listings where they purely rely on the average Joe who knows very little to get an easy sale.

For a first time buyer, reading some product descriptions without any background research simply gives false hope. A popular example of this misconception is that ‘8000K is brighter than 5000K’. This is completely untrue as kelvin is a measurement by ‘temperature’ of the colour produced. For overall brightness, you want to look out for the the amount of lumens that is produced.

Officially, halogen bulbs with a colour temperature rating of over 4200k are not legal for road use as they aren’t classified as ‘white’, which is odd when you see some cars driving around with lights so dim you have no idea how they haven’t crashed yet!

When we take a normal bulb and apply a thin blue translucent coating, the appearance transforms from the standard 3400 Kelvin halogen colour (white light with a yellow tint) towards a more pure white (filtering out the yellow at around 4000k). This is exactly what OSRAM Cool Blue Intense bulbs do; they achieve this by adding just the right amount of coating to produce 4200 Kelvin. The thicker the coating, the more the colour shifts towards a cold white light that produces a slight blue tint. However the disadvantage of deeply coated bulbs is quite obvious, the less transparency the bulbs glass has, the more light that is being blocked from exiting the bulb, thus defeating the point of upgrading them for performance in the first place. They are purely bulbs for a change in style, read on below for our recommended tinted bulbs. Just keep in mind that not all coated bulbs are made for styling only.



Osram Cool Blue Intense 4200K – 100% Road Legal – Styling Bulb

These are the bluest road legal high quality halogen bulbs you can buy (in Europe at least) they provide up to 20% more light and create that HID ‘Xenon’ look. A common misunderstanding is that ‘Xenon look’ doesn’t mean your headlights will look like a prestige vehicle with super bright blue tinted HID Xenon bulbs. It refers to OEM standard fitted Xenon Bulbs which are most commonly found to be around 4300K.


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Osram Night Breaker Unlimited – 100% Road Legal – Performance Bulb

One of the reasons Osram Night Breaker Unlimited (to the left) are so successful is because there is a clear ‘light window’ on the bulbs glass which is in-line with the tungsten filament(s).

This means you achieve full light expulsion at the brightest section of the bulb and style from the rest which is a good balance. We recommend these bulbs for a balance of performance and style, although these bulbs are great in the performance sector, don’t expect them to look like standard HID bulbs.



Osram Night Breaker Laser – 100% Road Legal – Performance Bulb

Night Breaker Laser is OSRAM’S latest halogen bulb. Unfortunately no it doesn’t produce a ‘Laser’ light which is what one customer actually emailed in asking about; but it’s filled with pure Xenon gas instead of halogen. This produces a far brighter white light than standard bulbs but they will still visibility look like a halogen.



Osram Cool Blue BOOST – Unfortunately not road legal – Offroad use only – Styling Bulb

To the left, OSRAM’s new range Cool Blue Boost helps combat the dimming problem from coating, they designed the new bulb with a higher running wattage for extra lumen output (brightness) than standard bulbs.

The other advantage is just over half of the bulbs glass is deeply coated in blue and the remaining section is slightly thinner, this helps produces a nice mix of blue and white. Unfortunately due to colour rating and wattage, these bulbs are not road legal. They are still great bulbs for off-road use though, such as track days, car shows etc. 


So take your pick, which is your favourite?