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is anybody else sick of those orange street lights, you cant see the road markings, all cars look the same colour, but this is the best bit - the government put up these lights because they are half the price of white lights, but they only last half the time, so you might as well have the white ones.
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These lights are sodium vapour.
Yes, the colour distortion is a pain in the neck, the red London buses look grey!
Thankfully, they are being phased out.
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wasnt the idea of using sodium lamps to increase visibility and not dazzle? Doesnt the orange increase contrast or something?
Makes me wonder because there are those yellow driving-glasses available which do a similar job i imagine.
And yes, monochromatic orange light is annoying. We want full colour!
At least it stops the debate over car colours at night - there all orange, orange or orange!
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The main reason for using sodium lamps was cost (as usual). At the time they were the most efficient technology in terms of lumens per watt, so reduced running costs which we all pay for in our rates and taxes.
As we all know, though, they only produce light in a very limited part of the spectrum. Modern developments have now resulted in efficient lamps with better colour balance.
Regards
john
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Not wanting to bore anyone but they produce light at two distinct wavelengths due to the stimulated emission of energy in the form of light as the electrons "fall" back to a lower energy orbital.
It is this light that the human eye is most sensitive to so, in fact, it should aid vision. It removes colour because colour comes from the relative reflectance/absorption of the differing wavelengths in the continuous spectrum emitted by, say, a tungsten filament or the sun (ROYGBIV). As the wavelengths produced by a sodium discharge lamp are so defined your car cannot look blue as there is no blue light to reflect (or red light to absorb).
Xenon gas discharge lamps such as those in modern headlights work the same way but produce distinct wavelengths in the blue end of the spectrum.
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Guy,
So why do those headlamps go from blue to yellow as their "platform" bounces over the challenging Fen roads?
David
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Guy! - the Hells Belles Ale you consumed last night in large quantities seems to have gone to your head and stirred up some university lecture memories!
BTW, we were at Ottery St Mary, Devon, at the Flaming Tar Barrels evening. Great fun. Didn't get in till 2am. Yawn...
You'd never see anything like that in the Fens (DJW!)
For anyone who is interested, check out www.tarbarrels.co.uk/
It could only happen in Devon!
Also, I dare anybody to ask Guy about the 'Generator Game' (Which he won!)
David
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Someone makes beer in old tar barrels? And I bet they serve it flat.
Jonathan
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The guy in the pic on the home page looks as if he's heading for anall day bender.
So go on then Guy, do tell we are all agog. I even promise not to say anything against LPG again.
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Flaming Hell
I just looked at that site. Looks like a fun packed evening.
Bet the Health and Safety Executive don't know about it though.
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It is serious as well isn't it?! Looks fun but you're not telling me that someone hasn't lost hair or singed some other attached body component at some point - still, maybe that is viewed as half the fun of it!
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Well - it goes something like this.
1. Drink some suspicous Devonshire "Real Ale" - approx. 10 pints.
2. The "Somerset Contingent" then see who can turn the portable generator off the largest kebab/hot-dog wagon in the most amusing fashion.
3. I won with a "drive-by" manouvere using the tried and tested - "Full Choke" method.
That Ben Nice But Dim chap from Countryfile was there so keep your eyes peeled - I'm the drunk idiot in the orange Helly Hansen and Dave is the bloke with the big nose.
DW now for the Anorak bit. The colour changes as the light is refracted slightly by the lens. These lamps are strongly focused and the thick material slows the light down(like a prism) effectively lengthening the wavelength and turning the blue to yellow/green. Red, orange, yellow, green, blue, indigo, violet in order of increasing wavelength.
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I hope that was a "driven-by" you meant. Re the 10 pints.
David
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.......I was on foot - and yes, Brother Lacey was driving.
More of a "walk-by" - well, a "stumble-by" at that point in the evening.
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Full choke as in....bit of a delay stopping and a devil to clear for re-start?
Wicked.
David
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Also the 'Turn the petrol tap off and watch what happens' worked well.
David
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