Supercalendering

Supercalendering is a finishing process used in the paper industry to produce paper and paperboard with a smooth, glossy surface. It is an extension of the calendering process, which involves passing paper through a series of rollers to flatten and smooth it. In supercalendering, the paper is passed through a stack of alternating hard and soft rollers, often heated. The soft rollers are typically made of cotton, paper, or synthetic materials, while the hard rollers are usually steel.

The combination of pressure, heat, and the resilient nature of the soft rollers allows the paper fibers to be pressed and deformed more effectively than in standard calendering. This results in a highly polished surface that enhances the paper's brightness, smoothness, and gloss. Supercalendered paper is often used for high-quality printing, such as magazines, brochures, and art reproductions, where sharp image definition and vibrant colors are desired. The process can also improve the printability and ink holdout of the paper. Different types of paper, including coated and uncoated grades, can undergo supercalendering, though it is particularly effective for coated papers to achieve a very smooth top surface for ink laydown. The specific configuration of the supercalender, including the number and type of rollers, pressure, and temperature, can be adjusted to achieve a desired level of finish and affect the paper's properties.