What gives MH its color spectrum?

[CodeBlue]

I know that in floresents it is the particular gas in the light which give it a specific color. i.e. 6500k, 10,000k, 20,000k.

What is the reason a MH bulb gives off a certain color spectrum? Is it the shape, length, or material of the filament? Just started thinking about this after a truck with blue headlights came up behind me. I guess I had nothing better to do while driving home tonight.

[blgreef]

metal halides do not use a fillamant, they have an open gap that an arc is generated across, the colour is generated by the mix of gases and the salts in the arc tube.

I would think final colour will also depend on the arc tube temp so arc tube design is also important

[CodeBlue]

Thanks