Difference of Calendering and Dochim Effects on Paper Surface Properties

Hanji is a traditional Korean handmade paper, which has been known in ancient Far East as an excellent quality calligraphic paper for more than 1,500 year. Hanji is mostly made of Korean paper mulberry bast fibers, and if properly processed, normally lasts for more than 1,000 years with significant strength and still recognizable calligraphic writings or drawings on it. Dochim is a special way of Hanji calendering process, but is turned out to be quite different from modern calendering (machine hard nip calendering) in several aspects. In Dochim process, mechanical impacts were applied vertically to the surface of papers. Compared to the modern hard nip calendering, the Dochim process increased paper gloss much more. The degrees of smoothness improvement and paper densification by the Dochim process were largely dependent upon the fiber types of the papers.