A waterbrush is ideal for using with watercolor paints, and eliminates the need for a separate container of water. This makes it really useful for plein air painting or sketching on location.
The photos above show one of the 12 pans (blocks) of paint in the small watercolor set I use when traveling. If I just want a little of a color, I touch the waterbrush against the paint. The moisture in the bristles will 'activate' the dry pan paint, and I'll have a little color to use.
If I want a lot of a particular color, I'll drop clean water down into the pan from the brush (Photo 2). How much I mix the paint and water with the brush depends on how dark I want the paint color be (Photo 3). The more I agitate the water against the paint pan, the more paint 'dissolves' into the water.
To use the watercolor paint, simply dip the waterbrush in and out the paint, like with a normal brush. If you're used to using a sable-haired brush for watercolor, you'll find that the synthetic bristles of a waterbrush don't hold as much paint, so you'll find yourself dipping the brush into the paint more often.
