TAPPI T 441 is a standard method for the determination of water absorption of sizing (non-absorbent) paper, Cardboard and corrugated fibreboard, using the Cobb test method. The standard specifies the amount of water absorbed by a specific instrument, such as a Cobb absorptor, over a specified period of time under standardized conditions, by measurement paper to assess its surface water-absorption. Test results are expressed in Cobb values in g/m ². The Cobb test method is applicable to sizing paper and Cardboard, but not to papers quantified below 50 g/m ² or unsizing. The standard provides a uniform water-absorption test method for the paper industry, which is widely used for quality control and product performance evaluation.