Foliation vs. pagination: numbering leaves, not pages

Foliation assigns one number to each leaf, including its front and back. Pagination assigns one number to each page. A foliated book of 100 leaves and a paginated book of 200 pages are the same size.

Manuscript catalogs may use foliation, pagination, opening numbers, quire signatures, or more than one numbering system. Cite the system used by the holding institution or catalog and identify it when ambiguity remains.

How the two systems map

Each leaf (folio) has a recto and a verso, so one folio number covers two page numbers:

• f. 1r = p. 1  ·  f. 1v = p. 2  ·  f. 2r = p. 3  ·  f. 2v = p. 4
• In general: recto of folio n = page 2n−1; verso of folio n = page 2n.
• Going the other way: page p sits on folio ⌈p/2⌉, recto if p is odd.
• The arithmetic holds only when both counts start together at the first leaf and nothing is missing, which, with manuscripts, is exactly what you cannot assume.

The conversion is valid only under the stated assumptions. Cite the repository's reference system rather than a page number calculated from foliation.

Why manuscripts are foliated

Partly history: medieval readers who numbered their books at all usually numbered leaves, and page numbering only became standard with print. But foliation also fits the object better. A leaf is a physical thing, one piece of parchment or paper, while a page is one face of it. When a leaf is lost or misbound, foliation records the event: the numbers jump, and the jump is evidence. Pagination can only describe an intact, ideal book.

Foliation is also, bluntly, half the work. A librarian numbering a 300-leaf codex in ink writes 300 numbers, on the recto of each leaf, usually the upper right corner. Nobody wanted to write 600.

One book, several numbering systems

Old books accumulate numbering the way they accumulate bookplates. It is completely normal to open a manuscript and find:

• a medieval foliation in roman numerals, abandoned partway;
• an early-modern ink foliation that skips a number where a leaf was already lost;
• a nineteenth-century pencil foliation added by the library, which is the one the catalog cites;
• and, in a few books, a medieval pagination (they exist) or a numbering that counts openings rather than leaves.

Use the foliation named in the repository's catalog, preferred citation, or current reference images. The newest-looking numbers are not automatically the preferred system. When scholarship uses an older foliation, state which one you cite and use a concordance if the repository provides one.

When the numbering is wrong

Repositories use several methods for repeated, skipped, inserted, or corrected numbers. A repeated number may receive bis, a letter suffix, an asterisk, or a new sequence. A repository may preserve an established erroneous foliation, refoliate the object, or publish a concordance. Copy its notation rather than imposing a local correction.

Flyleaves may be unnumbered, included in the main count, or assigned a separate roman-numeral or lettered sequence. Record what the repository uses.