Lol.It's jail, not the Hyatt hotel.![]()
Seriously though, lighting in CGI is a huge and interesting topic.
Take a look around the room you're in, and look at the shadows.
Even a single light bulb will reach all corners of the room, and it's the "bounce" of the photons off each surface, onto another, decaying as it goes, that lights up the darker areas that the light doesn't illuminate directly.
Paint one of your walls bright RED, and from a single light bulb you'll see a tint of red on most surfaces, and that's those wonderful photons bouncing off the red wall, and taking the colour information with them onto their next bounce.
Actually don't paint a wall red.
It's supposed to be a very angry colour to live with.

Smiley.