Working with a person is harder but much more dynamic than working from a photograph. When you’re working with a person, every time they sit, you see things you didn’t see before. It’s interesting looking at portraits that artists have done using the same model numerous times: you can see a resemblance, but the model doesn’t always look the same. Now we’re so used to defining reality in terms of photography. Portraiture was probably much easier before photography existed, because the idea of likeness was different, I think: approximate but also slightly flattering.