Report comment Reply snow says: March 31, 2013 at 3:47 pm sorry should have been more specific i was thinking of a Mercury vapor lamp not MH (closely related but not the same) MH is again full spectrum since it contains sodium and other trace elements a true mercury vapor lamp will have distinct spectrum peaks (7 acording to wikipedia <a href="http://en.wikipedia.org/wiki/Mercury_lamp">http://en.wikipedia.org/wiki/Mercury_lamp</a> of those 3 would have