[Semnoz]

Originally Posted by Tatsfield

Short wavelength blue light has less penetrative power than longer wave length red light, hence the last light to reach us through the extra atmosphere as the sun dips down to the horizon is red giving us red sun sets. In damp air a more yellow/white light containing a higher proportion of long wavelength light will throw a longer beam than scattered blue light. Blue light looks brighter but keeping the colour temperature towards the 4000° level will be the best compromise for all round beam length. The auto fashionistas like blue tinged bulbs but this harks back to the days when only exotic cars had HID Xenon lights and the early ones tended to look a lot bluer than they do now.

That's good to know thanks, as when I recently replaced my working but mis-matched pair of bulbs with Osram Xenarc Nightbreaker Unlimited (4300K), I was initially disappointed at the 'warmer' beam.

I think 6000K HIDs are useful for matching the colour of any LEDs that are running alongside them. Fortunately my 'old' car doesn't have any of those daft 'daytime running lights' or whatever they're called.