I drew the sketch above in Dulwich Park a couple of weeks ago, in early February. At this time of year, a quick sketch is all that is practical to do out of doors, but I have now used this sketch to make three different versions in watercolour. I usually paint using a primary triad – that is obviously red, yellow and blue – mixing all the other colours from these three. But they do not have to be the same three pigments, and there are many options to choose, which may be warmer or cooler colours, or creating a darker or lighter effect. In particular, these pictures use three different blues: French Ultramarine, Cerulean, or Winsor Blue. Here are the three images with their varying palettes.