I can confirm dor123's comment: Sc & Na (in that order) get reduced. M-H lamps eventually look much like MV lamps spectroscopically; however, there are differences making M-H lamps look bluer than MV.

This thread has stirred my interest to see what happens to MV lamps as they green-out. So I started looking for greened MV lamps I may have.

The Ideal Gas model states that the pressure is in linear relation to the temperature (if volume and quantity of gas are unchanged). This means that when there is no more liquid to evaporate and its vapor alone, When the temperature goes up from the Blackened MV arc tube, so does the pressure