TIL the uniform dark gray background color that many people report seeing in the absence of light is called Eigengrau or dark light or brain gray.

https://en.wikipedia.org/wiki/Eigengrau
#til #todayilearned
https://www.reddit.com/r/todayilearned/comments/1gqd0hn/til_the_uniform_dark_gray_background_color_that/