in bookbinding, pyroxylin-impregnated fabrics are considered superior to starch-filled fabrics because their surfaces are more water resistant, they are more resistant to insects and fungi, and they are generally stronger. they wear well and are particularly suitable for use in library binding where many people will be repeatedly handling the same books. pyroxylin also allows for unique decorative effects on book covers. they, too, are water repellant and immune to insect attack and fungi, but they do not wear as well as starch impregnated cloths because of cracking at the joints and occasional peeling of the coating.