I was reading a YA novel called 'Greylands' by Isobelle Carmody. Hell for me would be Greylands - a dull place with no colour. And actually for the protagonist it is a place of grief and loss, a place he visits after his mother dies. It isn't a good place.
A challenge to paint without colour was posted under one of my paintings on Facebook. It might be a good exercise but I want to paint the world in joy, and colour is my vehicle of choice. No Greylands for me.