The price of high-quality pure linen sold on the market is high. The price can also reflect the quality of linen. High-quality primary-color linen is brown, shiny and evenly absorbent. The flax is not good in quality. It is treated as a soft fiber flax, which absorbs water unevenly and will turn black after wetting. Check whether the thickness of the longitude and latitude lines is uniform through light transmission. If the warp and weft are too uniform, it may be cotton fabric.