CDM-T lighting

These are arc lights?

Never heard of that type of lamp, CDM stands for Ceramic Discharge Metal-halide, apparently known as Light Emitting Ceramic (by cannabis growers?)

Did not know Cadbury's Dairy Milk could produce light..... Sorry. Brian

Pretty much, they are discharge lights, like the earliest very bright blue-tinted headlights.

My only encounter with them was about fifty years ago, with Rank Strand

It had an hour meter on the back, and you changed the lamp religiously at 1000 hour intervals. If you didn't, it would eventually explode, so most 765s had grilles over the front lens, just in case.

I remember those. In TV, if you fitted a new bubble, it took quite some time before it 'aged' to the correct colour temperature. Bit of a problem if it happened during an audience show.

As these lamps are getting harder to find and getting more expensive I will have to find a new LED fitting (or three) next time they fail.

The LED light will never be as good or last as long as that lamp.

The lamp that failed was 8 years old and fitted during the shops refit.

The shop opens at 7am and closes at 9pm 7 days a week so it had done some good work.

An 'arc' light is not a discharge lamp, not in my books anyway. An arc lamp is a light provided by an arc struck between two electrodes, often carbon. A discharge lamp is a lamp that has a specific gas in an envelope of some sort through which electricity passes to make it flouresce.

I guess you *could* claim that a discharge lamp is an 'arc in a gas' lamp but it doesn't really work for me.

It always annoys me when crime stories talk about the 'arc lamps' lighting up the tent with the dead body in it, I doubt they were ever arc lamps and they certainly aren't nowadays.

How many crime stories ever get the technical details right? Except, perhaps, for the one the story is based round, and they've done some research.