In his landmark 1931 book An Essay on Typography, the British typographer Eric Gill discusses everything from the proper place for the tail of an ‘R’ to terminate to which type of word press might best serve the amateur typographer. He casts the printed word as sacred. But there’s one thing — a silent, steady workhorse found in nearly every book — that Gill fails to address: the lowly page number.

The functional role of the page number is simple: it provides order and sequence to a text. And while it is a supremely utilitarian design element, more thought is put into it than you might imagine. Should it go at the top or the bottom of the page? In the right or left margin? Or in the center? These are all conscious and deliberate choices made by designers.

The designer who is perhaps most responsible for modern page-number placement is Jan Tschichold. Born in Switzerland and educated at the Leipzig Academy of the Arts, Tschichold fled Nazi Germany in 1933 and eventually settled in London. From 1947 to 1949, he worked at Penguin Books, where he masterminded the uniformly elegant and simplistic design of the imprint’s paperbacks that persists today.

But Tschichold’s mark went deeper than just book covers; he created an entire set of house instructions for the company’s books. And for Tschichold, folios (the word used by designers for page numbers) were governed by the same principles he emphatically stressed in all aspects of book design. Chief among these principles was clarity. “This,” he wrote in his 1928 book The New Typography: A Handbook for Modern Designers, “puts [the new typography] into deliberate opposition to the old typography whose aim was ‘beauty’ and whose clarity did not attain the high level we require today.”

Tschichold was adamant that folios should exist to facilitate that logical sequence and provide a guide for the eye when skimming to quickly access needed information (“Reading presupposes eye movement,” he observed). To that end, his instructions for Penguin specified that folios should be the same typeface and size as the rest of the text, and in Arabic numerals.

One significant point of design that Tschichold abandoned was the practice of subordinating the organization of all text elements around an invisible central axis (stay with me here.) What that means is that a designer builds out all the design elements of a book from that nonexistent axis “as if there were some focal point in the center of a line which would justify such an arrangement,” Tschichold wrote. But this, he determined, imposed an artificial central order on the layout of a text. It was an illogical practice, because readers don’t start reading from the center of a book, but from the sides.

Good numbering begins on the first page of text, which is not usually the first leaf (a piece of paper on which there are two pages front and back) of the book, which is why the first numbered page of a book will often not be “1” but something seemingly incongruous like “7.”

For books that read left to right with folios on the verso, or back of the leaf, should always be even numbers, and those on the recto, or the right side of the leaf, should be be odd. A text always begins in earnest on a recto page.

In designing number placement, a good designer also has to take into account the needs of a book binder. Shona Dawson, a representative for the Glasgow bookbinding company Downie Allison Downie, told me that to make their job easier the preferred placement of the folio is away from the binding edge of the book block, called the gutter margin. Folios are rarely placed in the gutter because they can be swallowed by the spine if the binder doesn’t do the job right, and such placement makes finding a page quickly difficult. Richard Marston, a designer who worked at Penguin from 1995 to 2003, told me such placement “would only get approved for books where a design is deliberately unconventional.”

“I [also] prefer the page numbering to relate to the text content more than the edges of pages,” he said, “as trimming is often variable with mass market publisher[s] of such books.”

Merriam-Webster’s 1998 Manual For Writers and Editors accords with this, warning against placing page numbers in the gutter margin, lest they be swallowed up by the closing bend of the spine. But the Manual clashes with Tschichold’s instructions to keep folios the same size and typeface as the rest of the text — it says that they can be acceptably bolded or made slightly larger. The Manual does warn, however, that folios should “should never be distractingly large.”

Tschichold was adamant that folios should exist to provide a guide for the eye when skimming to quickly access needed information .

Merriam-Webster identifies two types of placements: “prominent” and “unobtrusive.” Prominent placement puts the folio on the top upper left and right of the leaf. Unobtrusive puts it anywhere on the bottom. The folios are placed in line with the running head (along which the chapter titles or title of the book rest) if they are at the top, but if the running head contains numbers the folios are better suited to the bottom of the page. The first pages of each new chapter dispense with the folio entirely to avoid clashing with the chapter headings.

Ultimately, the decision to make folios prominent or unobtrusive turns on what function they’re meant to serve in a particular book: a practical or aesthetic one.

David Pearson, a book designer who worked for Penguin from 2002 to 2007, explained to me how folio placement can be a practical endeavor. Numbers on the top outside column can be good for things like cookbooks, when “you might not be reading the book in a linear fashion.” With novel folios, however, “you can afford to almost hide them,” he said. Those folios can be placed center-bottom, where they’re “almost just used to anchor the page.”

Outside of the practical and the aesthetic dichotomy of the page-number placement decision there’s a third consideration: money. In trade publishing, there’s a “perceived value” in inflating ever so slightly the size of the book to make it saleable for a few extra dollars. “All publishers are guilty of this,” said Pearson. “You do get asked to contribute to that.”

Ultimately, the decision to make folios prominent or unobtrusive turns on what function they’re meant to serve: a practical or aesthetic one.

In such instances, the bottom-center page number placement becomes invaluable. Not only can the text column end earlier to accommodate the space of the number, but the outside margin can also be ever so slightly expanded, without the page number drawing attention to all that empty space.

This mercenary aspect of text layout is a feature exclusive to physical publishing; there’s little chance for such a sleight of hand in producing online texts. In designing online pages, social buttons (for Facebook, Twitter, etc.) can perform the compositional role pagination would play on a physical page. Some web designers call these “hygiene links,” and they can be used to fill in the compositional role that folios play. Online, it is far easier to use a search function than an index to find a particular passage in a book. The search feature also makes consuming digital books strikingly different from physical ones: linear experience becomes much less necessary, and there’s a diminished chance of stumbling across a section accidentally.

Page number placement can also take on an active role of its own. The independent publishing company Unit Editions has published books in which the page numbers of a two-page spread are paired together on one page. This decision reflects the two-page layout as an integrated form, and puts it in opposition to certain form of digital publishing where pages are viewed individually, as on an ereader. “In this context the Unit Editions approach can be seen as a small statement of their intent,” Richard Marston told me, “as they only produce books in print.”

Statement of intent, chronological guidepost, or cheap trick to inflate the length of a text, page number placement is anything but an afterthought. Behind these innocuous and overlooked symbols, I found many stories to be told.

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