The FW pearlescent colors are opaque and can be used to quickly decorate or embellish book cloth. Use the dropper tip to add color to the bristles. Holding the brush facedown above (about a handspan) the book cloth, draw your thumb through the bristles to make the splatters. The ink generally will wash off your hands with soap and warm water, but if you want to be perfectly sure your hands will be clean, consider wearing gloves.
The Mazuma Gold, shown here, is a bright gold that shows up well on most colors of book cloth.