Bookbinding mull is a cotton fabric with a loose plain weave, similar to medical gauze or a non-elastic bandage. The gauze is coated with animal glue, which stiffens the fabric and prevents fraying during the cutting process.
Paper-backed mull is a product that replaces traditional mull, crepe paper, or interlining. The fabric is adhered to a thin layer of paper, simplifying its application. Both mull and paper-backed mull create highly durable connections for the book block, ensuring long-lasting and sturdy bookbinding.