Princeton’s Umbria Brushes synthetic fibers provide an extra degree of stiffness to move and control color. Unlike natural bristles, which become soft and distorted when used in waterbased media, the bristles on these brushes retain their shape and stiffness. Each brush includes two shades of synthetic fiber, seamless gold colored ferrules, and a Velvetouch handle for excellent grip and control. They can be used with heavier mediums.