Skip to content
Skip to main content

Imposition and Format for Book Description

Wednesday, September 17, 2014
Submitted by Gary Frost

Imposition diagram

There can be confusion regarding description of paper books; the given book needs description of how it was initially made as well as how it appears. Either perspective can unfairly dominate. Makers best describe their own work, but, perhaps, they cannot. Papermakers, printers and bookbinders would also prefer their own exclusive explanations. Bibliographers and book conservators can bring the description up to date but some estimation will be needed for missing production information. And the later encounters with the surviving book bring other surprises and descriptive challenges.

Book imposition and format provide a good example of this descriptive dichotomy and its challenges. Imposition, or the print shop choice of paper sheets and dimensions and schemes of page layout on the press bed are decisions of makers alone. Format derives from the folded gatherings. Formats have traditional names such as folio, quarto, octavo or various other explanations such as twelves from sheet and a half. A format designation can be assigned during examination of a book but format alone that will not fully describe the book makeup.

If you wish a tutorial on identification method of book imposition and format you will not be disappointed. Two admirable narrations are the description of imposition by Gabriel Rummonds[1] and description of format by Tom Tanselle.[2] Gabriel, the printer, describes print shop methods and Tom the bibliographer, describes the format description methods. Both are aware of each other’s practice and perspectives. Still there is a curious feeling of difference in perspectives of these two narrative types.

Let’s relate the knowledge presented by Gabriel and Tom and, at the same time, also examine the difference of their perspectives. Imposition and format are complements of page assembly method and ultimately they reflect expedients needed to convey book content in a physical object. Imposition and format comprise a practical origami constrained by decisive, economic choices and production management. Practicality must also follow implications of font size, line length and number of lines per page. Such reality will dominate all book production, early and modern.

In most paper book production the cost of paper directly determines imprint investment and risk. In the hand sheet era “Paper could claim over two-thirds of the total production costs, and in some cases three quarters of cost.”[3] Book printing paper was also premium stock and each sheet would need to count, run through and, ultimately, fold to full use without waste. Print shop masters knew all the options of imposition and format choice and used these for greatest expedition and expedience and error avoidance.[4] Book designers, compositors and pressmen knew accuracy of every casting-off of content, form lock-up and every production move. Such focus should also convey to description of the products of such attentive work.

Retuning to description, distractions and displacements are not needed! Features such as laid pattern orientation, commercial sizes of sheets, grain direction, or options of self-backing impositions or page casting-off strategies can obscure a descriptive narrative of imposition and format. We should consider description of the relation of the various features. I would offer that book shape can be a good starting point. All through history the general shapes of various books are apparent. The squat shape of the parchment book, derived from a quartered skin, contrasts with a more elongated rectangle an echo of the ergonomic shape of the hand paper mold and of later conventions for cut paper. The squat shape of the quartered parchment book is reflected by the two-fold quarto paper format while a more elongated proportion is produced by a three-fold, octavo paper gathering. The extreme shape of the ancient papyrus book is best visualized as a folded square.

With the advent of machine made paper and larger, more powerful iron presses the options of sheet size multiplied. The basic two, three, and four fold (folio, quarto, octavo) gatherings can be multiplied or tiled over a larger area, both doubled, quadrupled and multiplied to fill the press bed. Here the ¼ portions of the sheet can be imposed as miniatures of the starting proportion. Likewise any starting sheet can be multiplied into impositions times four. Options of a one-third proportion cut from a sheet enable impositions in twelves and these can compound to simplified folded gatherings based on third sheet cuts.

Imposition, seemingly inscrutable at first, quickly assimilated into the print shop routines that, after all, were based on handling intricate arrays of assembled types. More daunting were risks of chaos and confusion as various jobs progressed simultaneously among various compositors, pressmen, correctors and printed sheet inventories. It is fairly miraculous to consider the achievements of early book printing in conditions that multiplied risks, uncertainties, and experiment including exasperations such as unintended dis-proportional productions of book gatherings.

Shape, meaning page proportion or aspect ratio, can also project bookbinding conventions. There we need to remember that the head to tail height represents a double trim while the width is only diminished by a single foredge trim. Another factor of book product shape is book thickness. Letterpress monographs range from a single gathering to one hundred gatherings or more in thickness. Blank and ruled paper stationery binding, by contrast, will feature a standard number of gatherings, including a consistent number of gatherings in the earliest long-stitch books. Finally, book shape is itself optimized for various handling and manipulation actions and this is ultimately the most relevant feature for the reader.

The reader uses the book after the process of imposition and format decisions that shape a physical book. Actions of reading further reveal the infinite possibilities of three-dimensional book shapes. Use and ownership provokes another descriptive sequence. Later interventions such as inscription, annotation or rebinding can modify the book. So can integration into library collections. This sector of reader and owner intervention adds evidence to be examined and described by the bibliographer and conservator.

Imposition and format recede in context with the accumulating features of use and intervention. So the bibliographer and conservator are confronted with a larger material subject. But the imposition and format remain to suggest how the book began. The paper book is a complex subject for description. Special prompts and special terms are needed.


[1] Rummonds, Richard-Gabriel, Nineteenth-Century Printing Practices and the Iron Handpress, vol.1, Chapter Eight, Imposition, Oak Knoll Press, 2004.

[2] Tanselle, G. Thomas, “The Concept of Format”, Studies in Bibliography, Bibliographic Society of the University of Virginia, vol.53(2000), p.67-115.

[3] Raven, James, The Business of Books, Yale University Press, 2007, p.50.

[4] for a reference in English there is great reward and insight presented in the four volumes on printing practice by John Johnson (self-published) in 1824. His chapter in imposition is magnificent including clear diagrams. Johnson, who would know the most complex job options, also mentions that all content “should be divided into fours, eights, twelves and sixteens, which is the ground work of all impositions,”. True to form, (is that another expression from a historical trade!) his book is a sampler of such basic impositions.