What Are a Printer’s Mark and a Custodian’s Mark in a Book?—Small Marks with a Long History
Photo: Brett Wharton / Unsplash
Anyone who has ever leafed through an old book—holding it spine-up and flipping through the pages from the back—may have noticed strange letters, numbers, or single words at the bottom of some pages that don’t seem to fit the text. This is neither a printing error nor a coincidence. Understanding what a colophon is and how it differs from a custodian’s mark allows us to view old prints and 19th-century editions in a completely different light—as the result of precise craftsmanship, in which every detail served a specific purpose.
What is a printer’s mark?
A printer’s mark is a designation—usually a letter, a number, or a combination of both—placed at the bottom of the first page of each printed sheet. Before the advent of bookbinding machines that stitch together finished blocks, books were assembled by hand from individual sheets, which, after both sides were printed, were folded into what are known as “signatures.” With larger print runs, the sheets would easily get mixed up or out of order, and the bookbinder had to know the correct sequence in which to arrange them.
The reference number solved this problem. Subsequent sheets were marked with letters of the alphabet (A, B, C…), and within a single section—additionally with numbers (A2, A3, A4)—which indicated the order of the pages within a given sheet. This allowed the bookbinder to quickly verify that the set of sheets was in the correct order before sewing them into the book block. This technical solution, dating back to the era of incunabula, persisted in European printing for several centuries and is today one of the fundamental elements by which bibliographers and antiquarians identify the layout of a publication and verify its completeness.
The Curator in the Book—Why Was It Used?
The “kustosz” served a similar, though slightly different, function. It is a single word (or the beginning of a word) placed in the lower right corner of a page, repeating the first word of the following page. By typesetting the text in this way, the typesetter left a sort of link between the pages—the printer and proofreader could quickly verify that the pages followed one another in the correct order without having to read the entire text.
Colophons were particularly popular in 16th- to 18th-century printed works; later, they were gradually phased out as typesetting and quality control processes became more organized. In many old books—especially first editions of Polish texts from the Enlightenment or Romantic periods—the colophon appears consistently on every page, creating a sort of textual chain visible to anyone who turns the pages carefully.
Printing Markings in Old Books—What Else Is Worth Knowing
The colophon and the publisher’s name are the most common, but not the only, printing marks found in old books. When analyzing an antique book or a nineteenth-century edition, one may also encounter:
- page numbering—the numbering of pages or sheets, which was not always continuous or consistent throughout the book;
- foliation—numbering of sheets (rather than pages), typical of earlier prints;
- paper mill watermarks—visible when held up to the light, helpful in dating and determining the origin of the paper;
- colophon—a note at the end of a book containing information about the printer, the place and date of printing; it was used especially before the title page in its present form became widespread.
For someone who appraises and describes old books, these elements have practical significance. The presence of a full, unbroken sequence of call numbers makes it possible to determine whether a copy is complete or if pages are missing—which has a direct impact on its value. We discussed this issue in greater detail in our article explaining why a book’s rarity and its market value are not always the same. Signatures and custodians can also be helpful in identifying an edition when the title page is damaged or a portion of it is missing—an experienced antiquarian bookseller can use them to determine which print edition they are dealing with, even without complete bibliographic data.
Summary
The printer’s mark and the bookkeeper’s mark are traces of the old printing workshop, where there was no room for chance—each sheet had to be placed in its proper spot, and each page had to follow logically from the next. For the modern reader, these are inconspicuous letters and words in the margins; for the collector and antiquarian, they are a valuable source of information about the structure and completeness of the volume. It’s worth paying attention to them when looking at older editions, because they reveal more about the book than might be apparent at first glance.
