12 Experiment with colours
I create a Multiply layer and lay down some colours. And here’s why I get rid of the greys: when starting to add colours, your pastel brush will pick up and blend some of the colours from the underpainting. And you don’t want to mix grey and get muddy colours. I use a very desaturated subtle green colour as the base, which mixes with the red, creating some interesting effects. Some parts of the face like the nose, cheeks and ears need additional colour to make the face pop out of the canvas.