Many years ago, a lighting technician made a comment that stuck with me.
She said, “If we do our job right, nobody notices us. If we don’t — ooh, boy.”
And that is the reason for at least some of the anxiety that precedes the first tech rehearsal of any show.
How will the scenery look under the lights? And the costumes?
Different materials reflect and refract light differently and under bad lighting, to quote my friend, “Ooh, boy.”
Any bird watcher will tell you the same thing.
On a beautiful sunny day, hummingbirds have iridescent ruby throats, mallard drakes have green heads, and bluebirds, blue jays and indigo buntings are blue.
At dawn and dusk, or on a cloudy day, these birds look black.
Because they are.
Birds appear blue because of the structure of their feathers. When sunlight passes through the feathers of a blue bird, light hits the dark pigments in the feather and is bent, refracting the blue wavelength of the spectrum.
Green is also a structural color. Green feathers are black. Tiny air-filled structures form a layer on each feather barb. Green light waves are reflected from this colorless layer of cells. The other colors of the spectrum are absorbed by the dark background.
This explanation is way oversimplified.
Just know that, if the natural lighting is good, our blue and green birds are stunning. In dim light, though, "Ooh, boy."