Standard cotton materials such as muslins, organdies, percales, calicoes, and sheetings differ only in the weight of the material, fineness of thread, hardness of twist, and method of finish. Ginghams have the thread dyed before weaving and fancy weaves are frequently used. Duck, denim, and some other heavy materials have very hard twisted threads and are frequently woven with a twill. Silkolene is a trade name for a fine cotton cloth with a silky finish given after the cloth is woven. Mercerized cottons make lustrous materials, such as poplin, imitation pongee, and numerous attractive house-furnishing materials. India linon is entirely cotton, as are outing flannel and canton flannel. Many tussahs, voiles, and economy linens and other materials with rather deceptive names are cotton materials made to imitate silk, wool, or linen.