In textiles, lustre or luster is a physical property that makes them appear bright, glossy, and shiny. The amount of light reflected from the surface of a fiber is referred to as its luster. The level of luster is determined by how light reflects off the surface. For example, round surfaced fiber reflects more light and appears shinier than fiber with an irregular surface. Synthetic fibers with a more regular surface seem brighter than natural fibers with an irregular surface, with the exception of silk, which has a regular surface.[1][2][3][4]