I'm trying to find out what are the desirable requirments for the metal halide lamp & ballast to be used in our projectors.

I'm still learning very much @ this point, so, bear w/ me if I seem a little ignorant please.

I know that we want a 400 W Metal Halide bulb w/ a center pointed light concentration so that our light source comes from 1 point. It seems that the slender bulbs (as sold by LL) are the most desired. I'm assuming that's because they're used b/c it's easier to place a reflector behind these.

Is one 400 W metal halide lamp better (brighter) than the next? What determines this? Is there a way to tell by a description/specifications if a lamp is a desirable one or not?

Also, is any 400 W metal halide ballast (eballast of coil) sufficient for our purposes? Again, is one 400 W metal halide ballast better than the next? What determines this? What's the desired spec.'s?

I apologize if this question has been asked many times &/or is 'pinned' on the site. If it is, I've missed it. I've searched around & have yet to find the information on this.

Thanks in advance for any help/comments/advice.

~Psylynt