It has nothing to do with IDL, everything to do with realistic rendering.  The ambient channel approach is adequate for large surface areas where you would expect a substantial amount of light to be shed.  However, smaller devices, TV's and monitors do not emit such an intensity as I stated earlier in the post and was ignored.  IIRC, Bagginsbill made such a statement in a separate thread and suggested supplementing light emission with spot lighting using material ambient at a low intensity to avoid washing out the image and casting an unrealistic glow.