I used to do some assisting work for a theatrical designer here in NYC. I was writing cues with him prior to the start of tech and after creating a dozen or so basic looks as a starting point, he said a curious thing to me.

“OK, now take the master down to 85%”

So I did.

“Leave it.”

The entire tech I had the master locked off at 85% as we made changes and re-wrote cues. As we worked the director would ask for lights to be brought to “full.” Brighter, brighter, brighter! Leaving the master locked off gave us some head room and kept us from over lighting the play. It was an artificial barrier we constructed and it got us to a better, more subtle design.

I tell this story as a lesson in relative brightness. It’s a lesson we all learn in school. Our brains are taught to seek contrast by setting a base line for whatever is the brightest thing in our visual field. As light levels diminish around the brightest thing, our brain actually makes them “darker” we perceive them as less bright by comparison.

Yet, you can’t look at the grid of fly rail of Broadway show without seeing dozens more fixtures than necessary to cover the acting areas. We all reach the same panic mode. We look over our plot, we see our areas are covered, but we worry…”Maybe this won’t be bright enough, maybe something won’t pop.” So we add lights, maybe double up. This leads to unnecessary lighting, wasted watts.

The relative brightness of Broadways shows, rock concerts, and performance in general has sky rocketed over the decades. This simply isn’t necessary. Not only are fixtures more efficient but the human eye hasn’t changed.

Trust Relative Brightness, there are other ways to impress an audience besides blinding them.