Twenty Hearts was painted a long time ago. Sometimes when inspiration isn't flowing I set up exercises for myself. (I have a big sign in my studio with Chick Close's quote, "inspiration is for amateurs.")
I never use frisket or mask. I think it's better to practicing refining one's brush skills and reliance on it is lazy. I suppose I have a perverse pride about this. (Oh those seven deadly sins. . . .) I also rarely use glazing or over-painting techniques. I prefer the clarity of a single layer of transparent paint. It emits more light and amplifies clarity of hue.
In order to maintain precise edges with watercolor, contiguous areas must be completely dry before another is made wet. If one wishes to lay down a large area that will hold smaller shapes that area must remain wet while the shapes within it must remain dry.
Twenty Hearts is quite small and the multi-colored wash area behind the tiny hearts had to be first wet with water around each one before color was added. When the area was completely dry each heart was wet and the colors laid in them to mix in the wonderful way watercolors do, as friends who combine to create new energies and have new experiences while remaining distinct and true to themselves.