Eigengrau

Eigengrau is a fancy word for the color gray that we see when it's completely dark around us. When it's super dark, like when you're in a really dark room or outside at night, you might think that everything is completely black. But actually, there's a tiny bit of light that our eyes can still pick up, even if there's no light around. This light is called “ambient light,” and it’s made up of really dim light that's always around us even when we can’t see it.

Our brains interpret this ambient light as a very dark gray color, and that's the eigengrau color. So, even when you're in a pitch-black room or outside at night, you're not seeing absolute darkness because of the ambient light, and that ambient light is this very dark gray color called eigengrau.