I don't really like blaming my tools, because I think it's the last refuge of people who don't actually know what they're doing, but I didn't have a good white pastel, and I finally made the long walk to the art store, and got a couple hard pastels (white and dark brown, for details), and a nice white with just a tiny bit of yellow, to get the colour right. I also got a few paper stumps to get the blending right, and help with the little details. I don't know if it was the new tools, or they just gave me a little more confidence, but on this layer everything just sort of fell into place. The colour is much better and the portraits considerably more accurate. I'm going to give it a couple of days, then maybe go back in and touch things up.