Quarto (book format)

In general, refers to the format created by folding a sheet of paper twice. It is typically more square in shape than a folio and can be of varying sizes. The term may specifically refer to a book between octavo and folio in size, approximately 11 x 13 inches. To make a quarto, a sheet of paper is folded twice, forming four leaves or eight pages. Also refers to a mid-sized newspaper, about 9 x 12 inches, again made by folding a sheet twice. For books, when laid paper is used, the chain lines are horizontal. The quarto was considered the most elegant format for published works in England in the early 18th century. With the mechanization of the printing industry in the 19th century, librarians began to apply the term based on the size rather than the way a book was constructed.