Paper making machines have an extra smoothing process called a calendar calendar consists of several rollers arranged vertically one upon the other, By running the almost dry paper web between the rollers under high pressure, the paper is compacted and smooth. The pressure applied to the web by the rollers determines the finish of the paper.
The primary purposes of the calender are can be summarized below.
Increase the quality of the final product.
Make the paper surface extra smooth and glossy
Gives it a more uniform thickness to the final product.