Here are two pieces of doodles. The top was done with black marker and highlighted with coloured gel pens. The second was drawn with a silver gel pen and not coloured at all. Gideon thinks the bottom one needs to be coloured. Madeline thinks the top was better before it was coloured. I think they are each different styles and to colour the bottom one would be too much, but the top one benefits from the shading and highlighting of the colours.