Xenon headlights provide a beautiful white light which may have a cold bluish tinge. But what if is suddenly takes on a violet glow or even pink? The answer is simple – it has come to the end of its life. Unlike incandescent lamps, xenon lamps do not suddenly burn out. It’s more of a gradual process and involves a considerable loss of light.
Design-conscious drivers get very annoyed by this violet tinge, particularly if only one headlight is affected. But in actual fact the loss of light is the more serious problem. Before a xenon lamp fails completely it loses around half of its original light. Admittedly it still produces a lot of light, and fortunately these lamps generally last for 2000 hours. Loss of light, referred to as degrading by experts, is something that halogen lamps and LED lamps also suffer, but in these cases it is only 30%. The decrease in luminous flux is certainly not a quality issue.
Instead, the effects have to do with the physics of the lamp. You have probably seen the same thing happen with fluorescent tubes. Their light also looks pinkish-purple towards the end of their lives. That’s hardly surprising because they use the same principle to produce light, namely gas discharge.
The only way to avoid the unsightly effects is to replace the lamps before they give up the ghost. This is known in the trade as „preventative exchange“ A practice that is highly recommended for xenon lamps. Replacing xenon lamps, however, is much more involved and time-consuming than replacing halogen lamps however. This should only be done by someone who really knows what they’re doing. After all, when these lamps are switched on there may be ignition voltages of several tens of thousands of volts. And special test equipment is needed for a wide range of cars. Not many people have that sitting in their garage at home. And don’t even think about replacing lamps by the side of the road.
It is important for both lamps to be replaced at the same time. Yes we know, xenon lamps are not exactly cheap. But some of the work is the same whether one or both lamps are being replaced. That will save some money, and time as well. If you have two lamps of different ages on your car it is bound to show. And of course both lamps should come from the same manufacturer because there are small differences in light color straight from the same factory. The differences from one manufacturer to another may be much greater.
If you like the look of cold bluish light you can upgrade to it the next time you are replacing your lamps. But beware of spurious claims such as color temperatures of 8000, 10,000 or even 15,000 K. The Cool Blue series from Osram provides not only an eye-catching blue but also the extremely important high output of xenon light. And the 4100 K of standard xenon lamps from Osram are ideal for good visibility on the road.