This paper is a study on the types and standards of the inner pages used in book publishing in the era of King Jeongjo(正祖) of the Joseon dynasty. Throughout the studies, we define that the inner pages is refer to the paper which used in the body of a book. After a thorough investigation on the records in Kunseopyoki(羣書標記) about the distribution of books in that era, it turned out that 25 types of inner pages were employed in publications such as Kanjangji(簡壯紙), Kyeongjoji(京造紙), Gojeongji(藁精紙), Kwonchaekji(卷冊紙), Dangji(唐紙), Momyeonji(毛面紙), Baekmyeonji(白綿紙), Baekji (白紙), Baekhyuji(白休紙), Byeolbaekji(別白紙), Boojeonji(不剪紙), Boondangji(粉唐紙), Seolbaekji(雪白紙), Seolhwaji(雪花紙), Ryeongjangji(嶺壯紙), Wanbaekji(完白紙), Wanjangji(完壯紙), Wanji(完紙), Ryedanji(禮單紙), Jangji(壯紙), Chaekji(冊紙), Cheoneunji(天銀紙), Cheopchaekji(貼冊紙), Chohwoobaekji (稍厚白紙), Taesaji(太史紙).
The most widely used type of inner pages was Baekji, and Baekmyeonji. The Chinese papers like Dangji, Momyeonji, Boondangji, Taesaji were also used in publications, though those were not as much used as Baekji and Baekmyeonji.
It is observed that the size of Baekji is 77.5×47.0㎝, and that of Baekmyeonji is 105.7×79.9㎝. After investigating the actual size of the book that matches the records about the distribution of books in the era of King Jeongjo, We can infer that the book was published by dividing a full sheet of Baekji into two equal parts or dividing a full sheet of Baekmyeonji into four equal parts.