Calculating exposure of practical overhead, dinner table

Hi Roger!

Rewatched The Reader recently (quickly have to say how much I admire the craft of blocking from you and Stephen in this movie), and I got curious about the dinner scene where you’re keying with an overhead practical and using the table as bounce to fill the actors’ faces, all while keeping spill off the walls.

I know there are many ways to approach a dinner table scene, but in this case I love the simplicity of the setup.

My question is about how you determine the right amount of light from the practical. Are you always working out bulb count, wattage, diffusion around the bulbs, dimming, using inverse square law to predict falloff? Or is it partly instinct built up over decades of knowing what this type of fixture will do in a given space?

My fear approaching something like this myself would be bouncing too much light into the ceiling and flattening out the room. So maybe this was a set with no ceiling, or black duvetyne rigged above?

Thanks for any insight!