That's much neater than my 'rough & ready' approach, which is to make an ambience mask, super-dial beyond 1.00 to luminous, render in Superfly...

Happens to be a quick way of turning an imported set's oft-multiple luminaires into 'real' lights. Not so good for 'artistry'... 

My Ambience masks need white for lit, black for not: Care, must be black black, as even 'very dark grey that looks black' may glow well when you turn up the dial...