Representative Papermaking Machines Surface or Dry-End, Treatments and Coatings After the paper is formed and dried, it is usually passed between multiple sets of heavy rolls (Figure 3.9.). This "calendering" operation has many variations, but the prime objective is to iron and smooth out the surface of the paper stock to make it more suitable for printing. Calendering also compresses the paper sheet, giving a denser product and a glossier surface. Starch is a typical surface sizing used to fill surface voids and reduce liquid penetration rate.Representative Papermaking Machines Surface or Dry-End, Treatments and Coatings After the paper is formed and dried, it is usually passed between multiple sets of heavy rolls (Figure 3.9.). This "calendering" operation has many variations, but the prime objective is to iron and smooth out the surface of the paper stock to make it more suitable for printing. Calendering also compresses the paper sheet, giving a denser product and a glossier surface. Starch is a typical surface sizing used to fill surface voids and reduce liquid penetration rate