So, what gas ionises with an intense and very 'clean' blue light ? A few of
these lamps have sprung up around my town. A couple light up some pieces of
art school stainles steel 'sculpture' in a local park. I hadn't taken too
much notice of them, until another example appeared on the top of a tall
pole, illuminating the vehicle compound of a premises on the same business
park as my wife's place is.

The lamp itself looks like a typical high pressure sodium type - basically
tubular with a bulge in the middle. But the light it gives off is an
extremely intense blue. What's in there, and what is the rationale behind
illuminating a compound with this colour ? Seems to chase off the shadows
pretty good, but I wouldn't have thought that it suited CCTV very well ?

Arfa