A waterbrush is ideal for turning watercolor pencil into watercolor paint. You simply run the waterbrush over the watersoluble pencil, and the water in the bristles turns it into paint. The advantage of doing this with a waterbrush rather than an ordinary brush is that you don't have to stop to load the brush with water.
Photo 1 shows watercolor pencil with a waterbrush run across it just once. Photo 2 shows it having been done several times, which is why there's more paint 'activated'.
