Hey, Aurelia, I was just thinking about you Friday! My 11-year-old is fascinated by stage lighting now. I was telling him about footlights and then I wondered -whatever happened to footlights, and when did they go out? When I was doing amateur theater as a teenager, we still used them.
Oooh, the history of stage lighting. When stages were lit with candles or oil lamps, the lights lined the edge of the stage because that was the closest they could get to the actors. Then came lenses and reflectors and electricity which meant the stage could be lit from further away. Then someone figured out that if they put the lights up over the audience they could make a more realistic looking picture. A much more detailed timeline can be found here [link] . It's a neat read just because things have changed so much, so quickly because of changes in technology.
Footlights still exist in some places for the same reason mom always cut the end off the ham before baking it. 'Cause that's how it was always done.
Have your son look in a mirror and use a flashlight to light his face from different angles. Light from below is spooky and unnatural because all the shadows are in the wrong places. Sometimes this can be useful in a show, but more often than not it isn't really the desired effect.