As I said, I've been reading a lot about oil painting techniques, discovering the idea of underpainting and fat on lean. I've found that previously I've worked wet on wet, but I'm fascinated by the idea of letting underpainting show through broken colour on the final painting. So, whilst half-dreaming last night, I came up with a scheme of colours to use for my underpainting which, on reflection in the morning, are mostly complimentary colours of those in real life.
The underpainting was done in acrylic because I was scared to use the palette of oil paints I bought recently. They are 'artists' grade paints, rather than the 'student' grade I'd previously used, and the palette was suggested by the chap in the art shop (more about that later).
After I did the underpainting, I did some exercises with my new paints; looking at the values of the raw colours, and then making a large grid of secondary colours, plus titanium white. This second exercise was fantastic, and I discovered some, amazing browns, and purples. Adding the white to the corner of these secondary colours was an eye opener, creating great skin tones and greys.