While the tone is drying, I pre mix some of the colors I see. Here I have a green for the base color of the plate, some blue green for the shadows on the plate, and a more yellowish green mix for the very light spots on the plate. When the tone is dry, I start with the darks. This is mostly a mix of alizarin and sienna and ultramarine. The really dark darks are the most fragile, they get diluted the most quickly and then lost, so I paint them first, and try to be as accurate as possible. Some of the other deep darks are alizarin and pthalo green, which is almost a black.