Sorry Chad. You’ll have to make sure your “Z” key is switched on for this one, but it’s one of the questions I get asked so very often. What *is* it with me and streetlights? I’ve never been able to firmly put a finger on this one, but whilst typing an email to Wayne about my hatred of blue LEDs (that’s a blog for another day), I made an interesting connection, and to explain this, I’ll quote slightly from the email I wrote.

Anyway, Beastbits2 arrived the other day, and it has a great big blue LED power button which lights up the entire mercuryvapour.co.uk press office. It got me thinking about how much I hated blue LEDs, and it came to me is that one of the reasons is that they were so “fuzzy”, and so, here begind the email quote…

“I’ve never been able to see blue lights properly. If, for example I had to read three neon signs, one in red, one in green and one in blue, I would have to refocus my eyes in order to read the blue one. This, totally unintentionally, has just made me realise one of the reasons why I love mercury vapour lighting so much. New lamps, to me, always had a bluish-violet glow around them, especially against the night sky. This is, as I’ve just worked out, down to one of the few spectral peaks of mercury lamps being in the 400-450nm wavelength area, which appears blurred to me, but the rest of the lamp’s output appearing normal, therefore, new lamps would always have a pleasant, deep blue haze around them…. not so pleasant now that I realise it’s a vision defect!

It would also explain why I’ve never been able to take a satisfactory picture of a mercury vapour light the way I see them, and why I can instantly distinuigh this particular light source from similar technologies such as metal halide.

For the record, I wrote that a couple of days ago and Wayne hasn’t replied to the email. I guess it was THAT boring!