Bibliographic format refers to the proportional relationship between a full sheet of paper and the folded and cut leaves of a book. For example, a text printed two-up so that the sheet of paper needs to be folded once to make the leaves of a book is in "folio" format. A book printed four-up on a sheet that's folded in half, then in half again, is a "quarto" and so on.
Confusingly, in the 19th century many of the terms started to be used as general indications of a book's height, where "folio" means "big", "quarto" means "ordinary size", and "octavo" means "little". As a result, when someone at the Folger refers to "a folio," you have to rely on context to know if that means an oversize book, a book in in folio format, or one of the first four editions of Shakespeare's collected plays.
Abbreviations and names for formats include:
|DCRM(B)||Gaskell||Ordinary spoken English||Latinate spoken English||Other|
|full-sheet||1⁰||broadsheet, full sheet|
|fol.||2⁰||folio||folio||fo., 1/2⁰, f⁰, F|
|4to||4⁰||quarto||quarto||1/4⁰, Q⁰, Q|
|long 12mo||long 12⁰||long twelvmo||long duodecimo|
|long 24mo||long 24⁰||long twenty-fourmo||long vicesimo-quarto|
- Descriptive Cataloging of Rare Materials (Books), the international standard for rare books in library catalogs.
- Philip Gaskell, A New Introduction to Bibliography. Reprinted with corrections in 1995. New Castle, Del.: Oak Knoll Press, 2007