By Brandon Baldwin
Someone asked me the other day “why do some headlights appear blue while others are yellow?” I would like to answer, “well, the new trend now is to tint your headlights. All the kids are doing it now-a-days.” But, that would be lying. It has more to do with light intensity. Regular light is white, which is a combination of all the colors. Remember ROYGBIV, which is the rainbow of colors where RED is the first and the shortest wavelength. YELLOW is in the middle, which is what the old, dimmer headlights look like. And, the plastic lens headlights that get scratched and dull start to appear more yellow as they become more scratched and dull. This causes more light distortion, making the light appear even more yellow.
Ever been blinded by those pesky bright blue lights? Although they still contain all wavelengths, they contain more of the high end of the light spectrum, the blues. These are the shortest wavelength. Many of these are from cars that have HID or high-intensity-discharge headlights. Unfortunately, these blue wavelengths are more likely to bounce off water particles, making vision a little worse, not better.
There are replacement light-bulbs that are halogen bulbs that claim to be Xenon or HID light bulbs. HID require the use of an ignitor and a ballast to get them started. If you are just replacing a bulb in a vehicle that didn’t have HID to begin with, it’s not an HID bulb. The companies that claim the bulb is Xenon or HID have tinted the bulb with blue. This increases dangerous glare.
But, remember when hot rodders used to put the blue dot in the taillights? It was to make the light appear pinkish-purple because the eye can easily focus on the red, but not the blue. Cool, eh?
For older cars that switched from 6 volt to 12 volt, they see an increase in light intensity too. Even the sealed beam headlights have become halogen so that they are brighter. How did we ever see at night without the light levels we have now? And, if you like customization, now you can even buy sealed beam headlights for your old car that are not only halogen, but can have an amber ring around the outside, which you can wire to be the turn signal. Lighting for hot rodders has come a long way.