A creasing matrix, also known as a creasing rule, is a tool used in the printing and finishing industry to create sharp, clean creases in paper or other materials. The matrix is typically made of metal and consists of a series of parallel rows of sharp, raised edges.

When a sheet of paper is passed through the creasing matrix, the raised edges create indentations in the paper, which make it easier to fold the paper along a straight line. This is especially useful for large print jobs, such as brochures, catalogs, and instruction manuals, where multiple pages need to be folded accurately and consistently.

Creasing matrices come in various sizes and configurations to accommodate different paper sizes and folding patterns. Some matrices have adjustable settings, allowing the user to customize the depth and spacing of the creases.

Using a creasing matrix can improve the overall quality and appearance of a printed piece by ensuring that the creases are straight and well-defined. It can also save time and reduce waste by making it easier to fold the paper accurately and efficiently.