Lighting diagram for a green screen

Two jobs that must not touch: light the screen evenly, then light the subject like the plate you are keying into. The screen gets a pair of wide soft sources at matching distance and level, and the meter walks the surface until it reads flat. The subject stands as far off the screen as the room allows, so the spill dies and the rim can do its work: nothing sells a key like a clean edge. The rim's colour comes from the destination plate, and that decision belongs in prep, on this drawing, not in the grade.