I love James Gurney’s sketchbook portraits, often done rapidly with the subject in front of him. This was an attempt to imitate his style using gouache to paint from a paused video. I took heart from watching how he builds up detail from seemingly formless swirls of loosely applied colour using opaque gouache. He also uses casein, but I’m not sure if that’s available outside the US.

I found the gouache dries to a slightly lighter colour, and fresh layers can reactivate the paint below if they are too wet and worked for too long. As always, it’s hard to know when to stop: there’s always more detail to add or corrections to be made. Sometimes it’s useful to keep on painting, just to see what will happen. Other times it seems best to stop early and use later paintings for further experiments.