Pile reversal refers to a permanent change in a carpet’s appearance caused by the difference in the way light reflects off the sides and tip of a yarn as the pile lays in different directions. Shaded areas appear light from one direction and dark from another direction. This effect is generally noted in smooth surfaced, densely constructed, plush carpets (i.e. not in looped pile). Its cause may be foot traffic and once it occurs it is a permanent condition. The effect is often more visible after cleaning of a textile as dirt and grime may lower the reflectance of the fibers and make the issue less visible.
Synonyms in English
watermarking, pooling, puddling, shading