Deweighting, deweighing or weight reduction, is a chemical treatment that peels the surface of polyester fibers and makes them softer and finer. It also reduces the fiber weight and hence weakens the strength. Additionally, the treatment enhances the absorbency of the treated substrates. Deweighting is an alkaline hydrolysis treatment that affects the surface fibers of the polyester and reduces the decitex or denier of fibers, weight loss of between 10% and 30% is possible during the treatment. Polyester and cotton blends can be treated with an alkali process to make them look and feel like silk.