I’m keeping the backgrounds in a few shades of gray for several reasons. It’ll help the characters pop. I can focus the players attention to an important detail or object by adding a desaturated color like in the image with the monitor and boxes. The detail of the backgrounds won’t get lost in whatever crap color I would choose. And even though it’s not even close to being in the same league as Maurice Noble’s work with Chuck Jones, I still draw inspiration from his sweeping patches of value.