Apparent colour difference between areas of the same carpet caused by normal wear and the resulting random difference in pile lay direction. It is a characteristic of all cut-pile carpet and is most pronounced in singles plush. It is not a manufacturing defect. The physical cause is the difference between cut end, lustre and side lustre of fibres. The sides of fibres reflect more light and appear brighter and lighter in colour than the ends which absorb more light and appear to be duller and darker in colour.
