I've never painted a room in my home completely dark until a couple of weeks ago, when I decided to get rid of the white walls in my office and go a full on, really dark black/blue colour. When I did a complete overhaul of the room towards the start of the year, I dipped my toe into 'the dark side' by painting the chimney breast and the adjacent wall, which was going to be a gallery wall, in a deep, dark navy colour. On the remaining two walls, I painted them a muted white with grey undertones. The reason that I did this, to be honest, was because I was actually scared of painting the whole room dark.