The Shape of Paper

La feuille de papier, comme tout objet moulé, reçoit donc une empreinte parfaitement distincte et caractéristique, image de la forme sur laquelle elle est faite. Ce sont ces empreintes, ou images, qui permettent de classer les papiers, de reconnaître leur identité ou de constater leurs dissemblances.

Charles-Moïse Briquet, ‘Papiers et filigranes des Archives de Gênes 1154 à 1700’ (1888)

I should mention what is perhaps the most neglected single aspect of paper study, at least in the fifteenth century: paper sizes. I must confess that the importance of recording, and thinking in terms of, paper sizes has come upon me only slowly over the years, but I see now that it is really fundamental. It is also, like so much in paper study, very simple.

Paul Needham, ‘The Study of Paper from an Archival Point of View’, IPH Yearbook, vol. 7 (1988)

One may state almost categorically that the formats of small manuscripts have never been properly studied. As for small printed books, formats have been assigned to them by various incunable catalogues and bibliographies, but the assignments are often wrong; I suspect, indeed, that they are almost as often wrong as right.

Paul Needham, ‘Res papirea: Sizes and Formats of the Late Medieval Book’ (1994)


Let us get back to basics.

Sheets of paper are made with a mould, or rather a pair of moulds, at a vat.

The mould leaves its imprint on the object that is made.

Some of these signs are not voluntary, but intrinsic to the construction of the mould, in particular the dimensions, the distance between the chain-lines, and the density and thickness of the wires; others have no structural purpose, but were introduced intentionally to make the final product recognisable, such as the watermarks and other forms of decoration. For scholarly and other purposes, we have to turn this individuality to advantage, since if we can assign dates and places to these features, they provide access to information available in no other way.

As Briquet forcefully reminds us on more than one occasion, the identification of a sheet of paper, or many sheets of paper, as having been produced on the same mould, or same pair of moulds, rests on four factors:

1) the size of the sheet, which is necessarily modified by folding in order to make up a gathering, as well as by subsequent trimming and binding;

2) the wire-lines, i.e. their thickness and frequency (Briquet often marks where the sewing of the watermark to the chainlines has pulled them slightly further apart, leaving a gap, which he indicates with a thicker line. In my experience this is an helpful, sometimes decisive, distinguishing element, especially with very look-alike twins);

3) the chain-lines, most notably their distances apart;

4) the watermark(s) and the condition of the same (especially in their position with respect to the chain-lines, which he is scrupulous about indicating, whereas some other repertories even omit the chain-lines).

In their inspection of members of the opposite sex, human beings tend to be very particular about the difference between front and back; in the way they look at sheets of paper on the other hand, they do not seem to care, but the distinction is just as important. If you are trying to decide whether sheets of paper all come from the same mould, it helps if you have enough expertise to interpret the physical signs and look at the objects from the same direction (watermarks are sexy too!).

Whenever we approach the task of reconstructing the physiognomy of a sheet of paper through the format, we need to remember that what is put on a press to be printed, or is taken by a scribe to be written on, can have one of four different directions, i.e. mould-side up and right way up (if the work is a folio; with any other format the idea of “right-side up” is delightfully absurd); mould-side up and upside down; felt-side up and right way up; and felt-side up and upside down. When we add to the equation the fact that twin moulds are involved, the number of possible situations rises to eight. Bibliographers and paper-historians have not actually devised a way of describing the positions of the sheets of paper in a manuscript or in a printed book (this has to be good news, since any attempt would make the choreography of Nutcracker look like a morris dance). Anybody analysing paper evidence in detail has nevertheless be prepared to work out the relative positional equation (hint: model the sheet of paper and it’s simple enough!).

Easier said than done?

Undoubtedly. On the other hand, if you never start, you’ll never get anywhere. So let’s have a quick whip through the essentials, remembering always that a mould is a complex object and that, as with printing type, what we are studying is not the original, but the imprint it has left in another artefact. Since paper shrinks on drying, the original was larger than the trace it leaves: according to the make-up of the fibres and the thickness of the sheet, as well as the treatment it has received over time, shrinkage can vary (for instance, the experience of collating, using transparent photocopies, some Sixteenth-century books caught up in the 1966 Florence flood, during which, after a long soaking, they were disbound, washed to remove the mud, and subsequently rebound, sometimes encountered reductions of a couple of millimetres in the measurements of the printed type-page with respect to other unrestored copies).

Sheet-size and the Bologna Stone

It is obvious, all too obvious, to say that if two sheets of paper have markedly different dimensions, the watermarks they exhibit might be look-alike, but they cannot be the same (unless, of course, you are set on demonstrating that the twin watermarks were detached and attached to another pair of moulds; but such a demonstration requires filigranological skills of a high order). On the other hand studies frequently come to grief on this issue, since they do not take the elementary precaution of establishing their sheet-measurements and comparing them to those in Briquet. Les filigranes gives the sheet-size as the first element in the description and so you ignore it at your peril. If the measures do not match, you are barking up the wrong tree and need to try elsewhere in the wood.

Medieval paper in Italy has four basic sheet sizes. These are usefully summed up on the so-called Bologna stone and hereby lies something of a tale. Italian cities seem quite often to have affixed on public buildings plaques or stones establishing the official sizes for local manufactures. Another well known example, still in its original place on the Palazzo del Capitano del Popolo in Assisi, is a red stone with the measures of bricks and tiles placed there in 1349. It is accompanied by three pieces of iron giving the standard meaurements for cloth, i.e. the ‘canna’, the ‘passetto’, and the ‘palmo’. The Bologna inscription relating to paper sizes was first discovered, discussed and reproduced photographically by Briquet in his 1907 introduction (I, p. 3), whence it has been taken up on various occasions by others, who generally have not gone to the bother of actually going to Bologna in order to look at the original, which in 1912 was donated to the city [7]. Its original home, on the wall of a building at Via Accuse 8, Bologna, at the time home to the Tipografia Merloni, in an earlier epoch was the headquarters of the Società degli Speziali, or the Guild of Pharmacists, whose emblem – a pestle and mortar – appears on both sides of the inscription. The symbols are now much blackened by age and oxide, but direct scrutiny of the original shows that once upon a time they were gilded.

More than one scholar, writing about it, has stated that the stone is marble. I have traced this mistake (which I suspect is polygenetic) back as far as Gasparinetti’s article in Papiergeschichte in 1956, where he describes it as a “Marmorplatte”, something he repeats in other articles, and the error has been promulgated elsewhere, for instance in the important book on watermarks by Karl Theodor Weiss in 1962 (but the text was actually written between the two wars), as well as in writings by Needham. In defence of these scholars it has to be said that the line-cut used to print the image in Briquet makes it impossible to tell. In fact, it is a block of limestone, according to the museum’s experts, probably imported from Capodistria. Of course, if you’ve made the pilgrimage to Bologna’s Museo civico, where the stone is kept in the lapidarium, and set eyes on the original object, there is no way you are going to mistake it for marble.

Beginning with Briquet himself, writers on the history of paper have consistently linked this inscription with the text of the Bologna city statute in 1389, which contains a clause De facientibus cartas de papiro et earum forma, pretio, pena et diversis capitulis. Here is some of the text: “Statuimus et ordinamus quod quilibet magister qui facit seu futurum faciet vel fieri faciet cartas de papiro, teneatur ipsas facere seu fieri facere ad mensuram ordinatam prout et secundum quod continetur in marmore posito in muro contiguo palatii dominorum Antianorum super quo est curitorium ligneum dicti palatii in qua sponda muri sunt posita et affissa alia assadia seu mensure comunis Bononie, videlicet cartas imperiales, reales, mezanas et rezutas” [translation, with apologies for the original: we decree and order that anyone who makes or shall make or shall have made sheets of paper, is bound to make them or have them made according to the fixed sizes, which are shown on the marble plaque placed on the wall next to the Palace of the City Elders, underneath the wooden porch to the palace, and on the same bit of wall are found other standards or measures of the city of Bologna, and these are measures for Imperial, Royal, Median, and Chancery sheets] [7]. Now here of course we have an explanation as to why various people have made the above-mentioned mistake, since the document unequivocally refers to a text inscribed on a piece of marble. On the other hand, according to the statute, the block of marble is already on public display and thus must be earlier than the edict, though there is no way of knowing by how much. The other important point to be taken into account is that the original marble was affixed on the building, known as Palazzo d’Accursio on Piazza Maggiore, which from 1336 had housed the council of the city elders and today is still home to the municipality. It could not therefore have displayed the symbols of one of the city’s guilds. The stone known today is therefore a replica – probably a very close one – of a lost original: having examined the surviving artefact at leisure, especially from the style of the gilded emblems, I suspect that it is Sixteenth- or Seventeenth-century copy of the Medieval original; but for the moment this is only a personal judgement.

The text cut into the stone and filled with a black stucco reads, in Medieval-looking script and with Medieval-style word-spacing: “QUESTE SIENO LEFORME DEL CHUMUNE DEBOLLOGNA DECHE GRANDEÇA DENE ESSERE LECHARTE DEBA(M)BAXE CHE SEFARANO INBOLLOGNA ESSO DESTRETO CHOME QUI DESOTTO EDIUIXADO” [Figure 1]. Rendered into an approximate English, since the Medieval Italian is not exactly straightforward, it says: “These are the moulds of the city of Bologna, which say what the sizes of the sheets of cotton paper must be, which are made in Bologna and the surrounding area, as is set out here below”. There follow underneath four rectangles, boxed inside each other, in progressive sizes, labelled “INPERIALLE”, “REALLE”, “MEÇANE”, AND “REÇUTE”, which are of course the same four measurements prescribed in the statute.

Figure 1 The Bologna stone. Traditionally attributed to c. 1389, but perhaps a Seventeenth-century copy. Image by courtesy of the Museo Civico Medievale, Bologna, Italy.

The purpose of the stone is self-explanatory. In the case of a dispute about sheet-sizes, the piece of paper was placed on the stone and compared to the official measure, revealing immediately any discrepancy. The practical function is shown by the fact that the phrasing is in Italian, rather than in Latin, and thus available to people with perhaps only basic reading skills. It has been suggested that the text be taken very literally and that the moulds are meant to be compared to the stone, but this seems unlikely, both for practical reasons (carting the moulds in from some paper-mill out of town would have pleased no one) and for the fact that the text does distinguish between the forme (i.e. shapes or moulds) and the charte (i.e. papers or sheets), making it clear that it is the latter that are to be compared to the rectangles on the stone.

Some minor features in the text of the stone and in the nature of the rectangles require, however, additional comment, beginning with the word “bambaxe”, i.e. bambagia or “cotton”, to describe the nature of the fibres. Medieval and Renaissance paper, as Briquet took a lot of trouble to show at the end of the Nineteenth century [7], does not contain cotton fibres in any significant quantity; it is made up with linen and hemp. So where does the word “cotton” come from? We need to take a step backwards in time and understand that up to the Renaissance the Latin word charta, the equivalent of our modern paper, referred to parchment or vellum made with animal skin. When a new material appeared, in the shape of Arab paper imported from the Middle East, it is reasonable to suppose that there was some uncertainty about how it was made and what it was made with. Cotton, made from the flower of the Gossypium plant, was little known in Europe at the time, except as an expensive luxury material imported from the Eastern Mediterranean, together with silk. The problem is all too visible in the Medieval Latin terminology, in which the classical term for silk, bombyx (genitive bombycis), albeit a completely different substance, made from insect secretions, was extended to cotton, thus generating a long-standing ambiguity. In Medieval Italian a distinction appeared in time between bombacina, designating silk, and bambagia, which meant cotton, though the two terms were sometimes confused. According to the Nineteenth-century German scholar, Joseph von Karabacek, matters were further complicated by the provenance of some early paper from the city of Manbij (Arabic: منبج‎, Turkish: Münbiç), known in the West as Hierapolis Bambyce, also a cloth-making centre, near Aleppo (famous also for its brand-mark soap, made with laurel oil), in what today is Syria.

For all these reasons, when in the Thirteenth century documents in Medieval Italian begin to talk about paper, they designate it as bambagia or something similar. In Florence, for instance, the account book of Bene Bencivenni, written between 1262 and 1275, refers to a “quadernuccio dela banbasscia”; another document written in Prato in 1275 distinguishes explicitly between “quaderni di pechora”, or sheepskin parchment, and “quaderni di banbagia”, or paper; and so on [7]. Two centuries later, in the inventory of the manuscripts of the library of Borso d’Este at Ferrara in 1467, the document lists 148 titles, almost all of them distinguished on the basis of their physical support. The vast majority are on parchment, indicated as “in membranis”, while the twenty-seven paper and two mixed manuscripts are variously described as “in carta bombicina”, “in cartis bombicinis”, or “in papiro”. A later inventory, this time for the books of Eleonora d’Aragona in 1493, lists 71 titles, with the manuscripts in parchment described as in “charta de capreto” or “in charta buona”, while the eighteen paper items, of which half are printed artefacts, are listed as “in bambasina” or “in charta de bambaso” [7]. The advent of printing soon ensured the almost total demise of parchment as a book material, except for binding, and thus the transfer of the term carta in Italian (but also the Latin charta) to signify paper made with waste vegetable fibres.

Let us now turn to the four rectangles corresponding to the four different sheet sizes. Since Briquet first described the stone, rounding off his measurements to the nearest half centimetre, dimensions given for the same have oscillated in the scholarly discussion and so it is advisable to check whatever source you are using. In the following table the measurements provided in millimetres have been uniformed by giving the height, which is the shorter measure, before the width. There is a difference depending on whether the inside or the outside of the rectangle is taken as the basis of the measure. To avoid any insinuation of prejudice or favouritism both are given. In the final column is provided the ratio between the shorter and longer sides of the rectangle, based on the inner cornice.




Outer frame

Inner frame



500 × 740

510 × 740

500 × 725



445 × 615

450 × 615

440 × 608



345 × 515

350 × 504

345 × 490



315 × 450

318 × 450

310 × 440


The terms “Imperial” and “Royal” applied to large sizes of paper, albeit with some variations, remain in constant use for the whole of the hand-made paper period and beyond; “medium”, albeit with a greater oscillation, also survived for a long time. The fourth term reçute defines a sheet more generally known in Italian as “comune” and in English as “chancery” (itself a derivation from the Italian “cancelleresco”, i.e. the Papal administration): this is the essential dimension that, albeit with minor variations, will dominate the papermaking market for centuries to come, especially after 1500 and the advent of printing.

As a word, reçute has puzzled scholars and Briquet himself wrote that “la signification même du mot … n’est pas certaine”. In 1956, however, Andrea Gasparinetti cleverly suggested that the term derived from parchment making and stood for reciso or “cut”, i.e. it was half of a full sheet of Royal, which was the usual size derived from the animal [7]. The link confirms the close relationship maintained between parchment and paper in the Fourteenth century, which was only really broken by the advent of printing and the vast gearing up of the paper industry driven by the new medium. The sheet-proportions set-out on the Bologna stone therefore are not innovative; indeed it would be surprising if they were. They reflect a much older status quo, established by the handwritten Medieval book on parchment, which the city’s legislators faced with the new medium are rendering official.

Now here is an enjoyable little game to play on people who know nothing about paper and even on those who know quite a lot about paper. Take a sheet of modern A3 or A4 paper out of the nearest photocopying machine or printer: it is difficult to think of a more ubiquitous object or more representative of what we think of as modern civilisation. Project an image of the Bologna stone on a screen, hold the sheet of A3 or A4 in the beam of light so that it covers one of the rectangles on the stone: the audience will note with amazement that the proportions are (almost) exactly the same. Why? If we exclude that Bologna’s Medieval university, which had been in existence for three hundred years before the approximate date of the stone, had a science park where some time around 1300 photocopiers were invented, there has to be some other reason, such as geometrical.

The A and B series of paper sizes were established at an international level in 1975 with ISO 216, although they actually go back to the older DIN (Deutsches Institut für Normung, at the time called the Normenausschuß der deutschen Industrie) standard 476 of 1922. In the A series the measurements are as follows:

0: 1189×841 mm [= a physical area of 1 square metre]

1: 841 ×594 mm [= a physical area of 1/2 square metre]

2: 594×420 mm [= a physical area of 1/4 square metre]

3: 420×297 mm [= a physical area of 1/8 square metre]

4: 297×210 mm [= a physical area of 1/16 square metre]

5: 210×148 mm [and so on]

6: 148×105 mm

7: 105×74 mm

8: 74×52 mm

9: 52×37 mm

10: 37×26 mm

The A3 sheet therefore is a couple of centimetres smaller than the Medieval reçute shape, but maintains the same approximate proportions. In the DIN standard the ratio between the sides, albeit rounded off to the nearest millimetre, is 1 to 1.414, but refers to an irrational number, which, reduced to a mere 65 decimal places reads 1.41421 35623 73095 04880 16887 24209 69807 85696 71875 37694 80731 76679 73799. More simply, for those who, like myself, did so badly in maths at school that this figure leaves them totally perplexed, it is the square root of two, or 1 : √2, with which the ancient world knew as a Pythagorean constant [7].

A rectangle based on the proportions 1 : √2 has a special property: you can double it or halve it and the relationship between the sides remains invariant. (We are actually familiar with the fact from knowing that, if we run out of A4, we can tear sheets of A3 in half, but I suspect few of us knew that this trick has been around for nearly a millennium.) Equally interestingly, the rectangle based on the square-root of two seems to go back to well before the beginning of the Western book, since the sheet-sizes of Arab and oriental paper often, albeit not always, seem to have been constructed according to the same principle (unfortunately codicologists have not investigated the phenomenon with any sort of thoroughness; in fact I doubt whether most of them are even aware of it). It is a moot point as to whether the Medieval Italian parchment workers, who passed this precious snippet of knowledge on to the papermakers, were aware of all the geometry, since in cutting up an animal skin, this particular rectangle produces the least wastage. However, they knew enough to understand the principle and to construct their rectangles accordingly.

On the Bologna stone Meçane is half the size of Imperialle and Reçute is half the size of Realle: the latter fact leads to a circumstance that some manuscript scholars, but above all incunabulists, know from bitter experience, i.e. books with a mixed format, in which half-sheets of royal have been introduced together with full sheets in chancery. The fact that early printers frequently used a variety of sheet sizes has also caused confusion in the cataloguing history of some editions. Just to give one example, based on a census of all the extant items, the height of the surviving copies of the first edition of Pius II’s Epistolae in cardinalatu editae, published in Rome in 1475, vary between a minimum of 255 mm and a maximum of 290 mm (ISTC ip00710000) [28]. A book of the latter height would normally be a folio, but in fact the edition is a quarto printed on Royal paper, albeit with one sheet reset and printed on two sheets of Chancery, so that technically the format is mixed. In any survey therefore the sheer amount of variation that copies, which were once identical, have acquired in five hundred years of separate history remains a daunting obstacle.

The Fifteenth-century, and Afterwards

By the final quarter of the Fifteenth century intermediate sizes entered into circulation, in addition to the four basic measurements represented by the Bologna stone. Clearly the demands of the printing press and the rapid rise in the request for paper brought about by the new medium played the main part in their divulgation. The first scholar to draw attention to these different measures, with due nomenclature, in a series of brilliant articles, has been Paul Needham [7]. Taking the year 1500 as a cut-off point, six new measurements, all but one defined by Needham, can been recognised, as follows:

● “Gradual/Antiphonary”. Not discussed by Needham, perhaps because already well known, but famously the largest book, in terms of its physical height and breadth, published in the Fifteenth century was the 1499 Gradual published in Venice by Lucantonio Giunta on 28 September 1499 (ISTC ig00332000). It was followed by the four volumes of the associated Antiphonarium in 1503-04 and a Psalmista in 1507. These remarkable editions, printed in red and black, with extensive musical notation and appositely cut woodcut initial letters, must have been enormously costly to produce and required an extra large sheet, measuring approximately 520×760 mm, which was also exceptionally thick and strong, almost leathery in its consistency. Copies were also produced on parchment.

● “Super-royal” or “Law-royal”, present in Italian legal editions from the 1470s onwards. Copies in folio format in their original binding measure approximately 420-440 mm in height, so that the original untrimmed sheet, with its deckle edges still untouched, might have measured up to 480 mm in height, while the width perhaps broke with the tradition of the invariant rectangle and remained much the same as Royal, i.e. 615 mm. The outcome in folio format is a rectangle that appears narrower and higher, and thus more suitable for legal texts with lots of surrounding commentary, than its Royal cousin.

● “Super-median”, or a larger than Median size, is defined, for instance, in the contract to print the Lexicon graecum of Suidas in Milan in 1499 (ISTC is00829000), where the printers accept the requirement to print “dictum opus … in papiro in forma paulo maiori quam sit mezana” [translation: the said work in a size that is a little larger than Median] (I am grateful to Paul Needham for drawing my attention to this document and sharing his as yet unpublished work on this sheet-size). Larger than Median sheets were also employed in ambitious large-scale projects, such as the Bibles in folio format published in Venice by Scoto in 1489 or by Paganinus in 1495, where the unusual sheet-size is marked by the anomalous placing of a small watermark in the corner of the mould [see Chapter 5]. Extant copies of these editions possess heights that are consistently too small for Royal sheets, even heavily cut down, but are superior to the maximum measurement of a Median sheet. Again it seems reasonable to suppose the existence of a limited paper size, for these particular editions, with a dimension oscillating between a maximum of 400×565 mm and a minimum of 380×535 mm.

● “Narrow median” for the Aldine octavo format. Needham has convincingly demonstrated that the famous series of Aldine octavo editions of Greek, Latin, and Italian classics, famous as the first to employ Italic type, were also the first to change radically the shape of the small-format book. Aldus ordered and obtained from the paper mills a squarer sheet with dimensions approximately 350×420 mm, in other words a “Narrow median” with proportions of 1 : 1.2. When folded to make formats, such as folio and octavo, the proportions change and become 1 : 1.6, close to what is generally known as the “golden rectangle” (i.e. 1 : 1.618 ad infinitum). Although the invariant rectangle remained the basis of most papermaking moulds, this squarer shape was imitated in the course of the Sixteenth century in many other centres.

● “Super-chancery”. A slightly higher sheet, albeit with much the same width as Chancery, seems to have been prevalent in the Aldine shop in the 1490s, in particular in the printing of the great five volumes of Aristotle in Greek from 1495 to 1498, also in the 1499 Hypnerotomachia Poliphili. The measurements suggested by Needham are approximately 330×450 mm.

● “Half-median”. An unusual, smaller than Chancery, sheet, measuring approximately 255×360 mm, employed in particular in the Venetian printing shop of Franciscus Renner in and around 1480. The characteristic is that it is used together with a mix of half-sheets of Median in the several editions identified as employing this particular size of sheet.

When handling Fifteenth-century printed editions, it is important to understand that the different sheet-sizes are distributed in very different ways. In terms of quantity, Chancery sheets are increasingly common in printed editions in the last two decades of the Fifteenth century. Royal is the next most frequent size, and though less ubiquitous than Chancery, is relatively easy to find up to about 1480, especially for the printing of legal texts. Imperial on the other hand was reserved for special projects such as the 1493 Schedel Nuremberg chronicle. The most difficult size to identify is Median, since generally there is a possibility that it is a cut-down copy of a book in Royal sheets. Likewise the intermediate measures are not found in large quantities and can be tricky to identify: Super-royal again is associated mainly with legal editions; Super-median, Super-chancery, and Half-median are recognisable in relatively few instances, while the Gradual size used in 1499-1507 by Lucantonio Giunta was very much a once-off commission. 

Working out the original sheet-size in a manuscript or in an incunable requires expertise and experience. It is important to note not only the measurements of copies, but also the density of the sheet: the larger the original sheet, the thicker the consequent leaf. Apart from the complication posed by folding and formats, copies have obviously been cut down by the binder, so, where possible, it is important to base the assessment on a copy still in its original binding. Another good idea for printed editions is to collect the measurements of copies described in catalogues (with the proviso that not all cataloguers are clear whether their measurements are for the binding or for the leaf, and also that the largest collections, which most helpfully provide indications about the size of copies, such as the British Library (BMC) and the Bodleian (Bod-Inc), have a high proportion of copies in modern bindings).

In the process of identification one generally departs from the assumption that the watermark is regularly placed at the centre of the leaf in a folio format (or one chainline in towards the true centre in many Fabriano papers). Complications can arise, however, when slightly different sizes are mixed together. For example, the Venetian edition of the chivalric romance Merlin, published in 1480 (ISTC im00498500), is in a folio format, while copies vary in height between 257 and 302 mm. Normally this would be a chancery measure, but most of the watermarks are markedly off-centre, generally in the inner column, though sometimes in the outer. What plausibly happened is that a supply of median sheets was used for the edition and deliberately placed in an off-centre position on the tympan, leaving a large margin at the bottom and on one side, which was subsequently cut away by the binder.

Another instance, and a book I invite people to look at if they get a chance (it is not rare), is the fascinating little Bible published in Venice by Franz Renner in 1480, where repertories of incunabula have struggled to recognise the correct format. Older authorities departing from Hain 3078 give it as quarto; the Gesamtkatalog der Wiegendrucke, n. 4241, followed by the Italian Indice generale degli incunaboli, n. 1661, describe it as mixed quarto and octavo; while an alternative interpretation, beginning with Pellechet and Proctor, followed by BMC V, 195, and the ever-modifiable ISTC, say that it is a mix of folio and quarto. This last indication is the most correct, but the format is only half the question, since the edition is a complicated pot-pourri of different sheet-sizes. One sample copy in the Franciscan library in Florence is made up with 127 sheets of folio Half-median, 67 half sheets of unwatermarked quarto Median divided before printing, and 41 sheets of folio Chancery, placed slightly off-centre on the tympan, while other copies also contain the odd stray sheet of folio Median, placed well off-centre on the tympan.

As far as understanding sheet-sizes goes, the Sixteenth century is mostly uncharted territory. Outside legal publishing in the first quarter or so of the century, where Median, Super-median, and Royal remain extant, Chancery is the dominant form, though this label probably covers a multitude of sins and sizes. By about 1540 over 80% of formats are medium and small, which lead the printers to order thin sheets of paper, but for obvious reasons reconstructing the original measures from today’s bound copies is a disheartening task.

Unfolding Formats.

When a sheet of paper or parchment is folded, its size inevitably changes and this introduces the bugbear of format, which is nevertheless the key to understanding all book structure [9].

The format of a manuscript or a printed book is defined by the number of times the sheet of paper made at the vat has been folded, though in the smaller sizes the same number of foldings can produce different formats.

If it has not been folded at all, it is a broadside or 1°. This format, however, ostensibly the most simple of all, generates numerous problems. First, in the inability of cataloguers (and bibliographers) to recognise it; second, in knowing what to call it. The earliest examples, in terms of printed texts, are single sheets, sometimes as halves or quarters, usually ephemeral and thus with a very poor survival rate. The principle obstacle to doing anything on a larger scale evidently was the binding, since the single sheets had to be mounted so as to be sewn, which was a time-consuming and costly operation. On the other hand, if a printer wanted to produce a very large book, sometimes in conjunction with large copper plates, this format was the best option. The earliest example I have personally encountered is the hefty Imperatorum Romanorum … Verissimae Imagines by Iacopo de Strada, published in Zürich in 1559, where single copies are 50+ cm. in height. Hardly surprisingly, perhaps a trifle disappointingly, the more prestigious standard repertories, such as VD16, the Italian SBN Libro Antico, the USTC, the UK libraries united in COPAC, unanimously describe the format in this instance as folio. Of course, “broadside”, applied to such a bulky volume, is not a happy term and one can understand people feeling uncomfortable with it. Alternatives I have noticed are “double-folio” (which is tautologous), “portfolio” (which is meaningless), “in plano” (which is Latin and thus difficult to understand), and “atlante” (advised by the Italian SBN manual, which appears limiting in terms of its category); on the other hand, the American manual, Descriptive Cataloguing of Rare Books, 2nd edition, Washington, Library of Congress, 2007, rule 5D1.3, suggests: “Use ‘full-sheet’ for publications made up of unfolded sheets”. This appears excellent advice and I should follow it.

If the sheet has been folded once, it is a folio or 2°. Printing manuals, beginning with Hornschuch's Orthotypographia in 1608, and their bibliographical counterparts invariably furnish diagrams of formats for the printed book. It is quite common, however, for archive documents to employ “agenda” formats, in which the fold is parallel to the long side of the sheet. For instance, the manuscript Zornale of bookseller Francesco de Madiis (1484) in the Marciana Library in Venice is formed with eight 20-leaf gatherings of chancery sheets, folded in parallel to the long side, creating a tall, narrow ledger, ideal for book-keeping purposes.

If twice, it is a quarto or 4°. Again, music books often employ an agenda format, in which the sewing fold is parallel to the short side of the sheet.

If thrice, it is octavo or 8°.

If four times, it is duodecimo or 12°, or it can be sextodecimo or 16°; and so on.

If the sheet of paper is made according to the invariant ratio 1 : √2, folio, quarto, octavo, and all the lesser formats based on folding in eights maintain the same proportions. Formats based on folding in sixes or twelves, however, such as duodecimo, 18°, 24°, 36°, produce a taller narrower rectangle. Music formats often employ solutions, in formats such as 4° and 8°, in which the rectangle is horizontal rather than vertical, involving a different folding pattern in order to sew the gathering along the short edge.

Though the measurements on the Bologna stone are not to be taken to the letter, since time and geography inevitably saw differences and the sizes themselves in two cases do not correspond perfectly to the invariant rectangle, they are necessarily a valuable departure point. The following table provides an indication, for the three most common formats, of what leaf-sizes become in uncut copies after folding. As well as the four sizes on the stone itself, measured on the basis of the inner cornice, the table includes the intermediate measures suggested by Paul Needham.

Fig. 2

Outer/inner frame












520×760 380×260 260×180
Imperial [inperialle]








Super or Law-royal 480×620 480×310 310×240 240×155
Royal [realle]








Super-median 400×510 400×255 255×200 200×128
Median [meçane]








Narrow Median (Aldine octavo) 350×420 350×210 210×175 175×105
Super-chancery 330×450 330×225 225×165 165×113
Chancery [reçute]








Half-median 255×360 255×180 180×127 127×90


In the calculation of size it is reasonable to assume that each binding in the history of a book results in the removal of a couple of centimetres for large formats (folio-quarto) and a centimetre for small formats (quarto-octavo and downwards, though on a fold this doubles). It is therefore important to gather measurements from as many copies as possible, including reliable indications of leaf sizes in those catalogues that do provide measurements before attempting a diagnosis.

At some point in history, library cataloguers decided that actually looking at the paper was too difficult and therefore adopted a system of standard measures, i.e. a folio was any book more than 28 cm, and so on. This sublimely unhappy piece of idiocy was promulgated on a large scale in card catalogues and in some printed sources up to the end of the Seventies, when it quietly disappeared. So far I have not discovered where it originated, but it seems to have derived from publishing practices in the Nineteenth century [9]. Its wholly erroneous practice and conceptual laziness probably accounts for a fair number of the bad and mistaken indications relating to format that persist in various bibliographical repertories, though it should be said that these are being gradually identified and weeded out. As matters stand, however, any indication provided about a format inferior to 16° in a catalogue should be treated with caution (and in some cases even this assertion is over-optimistic).

The make-up of gatherings adds a further complication to the problem of correctly diagnosing a format and consequently the structure of the book.

From the binder’s point of view, when the book was a folio, there was no purpose in treating each and every sheet as a separate gathering and so printers had no difficulty in adopting the solution, prevalent in manuscript culture, of constructing gatherings with several sheets of paper sewn at the centre, so that bibliographers speak of a book as gathered in twos (one sheet), fours (two sheets), sixes (three sheets), eights (four sheets), and tens (five sheets); much beyond this point, the strain on the sewing at the centre tended to exclude larger constructions, although cases are known. Chronologically, incunables tended to favour gatherings in eights or tens; in England in the Seventeenth century gatherings in sixes were commonplace, the exceedingly famous example being the 1623 Shakespeare First Folio.

If the format is quarto, it is not uncommon for the sheet to form the whole gathering, but it is even more common for it to be gathered in eights, i.e. a second sheet is placed at the centre of the first. In this structure leaves belong to the outer sheet and leaves to the inner sheet. Together with octavo, the latter is the most frequent of all book structures. Some early English printers, however, employed quarto formats with six-leaf gatherings, i.e. a full sheet and a half-sheet in the middle.

If the format is octavo, in most cases the sheet and the gathering coincide. The same is true of duodecimo, although in France in the Seventeenth and Eighteenth centuries printers were fond of quiring them as successive gatherings of eight and four leaves, each pairing being from a full sheet printed as a single unit. Take note, however, that printers had two radically different approaches to duodecimo. The older solution is substantially Venetian, in which the layout was parallel to the long side of the sheet (horizontal chainlines) and a strip at the bottom of the sheet was cut off to be placed at the centre of the gathering; in Northern Europe, however, printers preferred the long 12°, in which the layout is parallel to the short side (vertical chainlines) and the gathering is folded accordion-wise, without having to cut off a strip, so the result is the same height as an octavo, but was much narrower.

If we go a step further down the rung, into formats such as sextodecimo, the sheet is generally divided between more than one gathering. Printers did, however, have the option of using half-sheet imposition, in which the text of the gathering was set in its entirety in the same forme, which printed both sides of the sheet; each sheet thus generated two copies and had to be cut in half and separated before the book was bound. (But if you want to explore these arcane matters more fully, you really want the parallel course on analytical bibliography, where these problems will be explained with admirable clarity.)

Among the smaller formats it is also possible to note different habits and preferences in the various geographical areas. In the Sixteenth century duodecimo format was hardly ever used in France, the exceptions being mostly books in Italian. The format Lyon printers, especially a firm such as De Tournes, preferred was conversely sextodecimo: in one sense, therefore, this is not an Italian format, but the close links between Lyon and Venice meant that it was often imitated in peninsula centres, mostly for texts in Latin being exported back over the Alps. Other formats that characterise particular geographical areas are long twelves or twenty-fours, in which the first fold of the sheet is parallel to the long edge. The Elzevir firm in Holland and Belgium used these distinctive formats for their prestigious series of classics.

If this last page and a half has troubled you, do not worry, most Medieval and Renaissance books employ large and medium formats, which are simple enough to identify. It is difficult, however, to obtain precise figures across a number of centuries, and any and every consultation of online repertories gives wildly variant results. As an alternative, a number of years ago, I spent a week ploughing through the entries for the books printed in Italy recorded in the first two letters of the alphabet (A-B) in two printed catalogues, i.e. the Indice generale degli incunaboli (IGI) issued in 1943, updated in 1981, and in the Edizioni italiane del XVI secolo, of which ‘B’ appeared in 1989 and the revised ‘A’ in 1991. The operation involved a fair amount of bibliographical manipulation and compensation, since some authors, even well known ones, have different headings: most notably Dante Alighieri, who is entered under his name in the incunable repertory and under his family name in the Sixteenth-century follow up. Albeit largely overtaken by events, the table that resulted provides a useful little summary of the relationship between the different formats in Italian publishing of the said period of 135 years.

Fig. 3



























































































% small formats

















Up to the end of the Sixteenth century, as the table shows, the extremely small, difficult to diagnose, formats are produced in almost negligible quantities. An edition of Dante was published in 18° in Venice in 1545, while early in the century a virtuoso (show-off) printer such as Alessandro Paganino experimented with a series in 24° [9]. Formats become more problematic in the Eighteenth century, when presses improved and thus were able to print larger sizes of sheet, while in the Nineteenth century the introduction of the iron hand-press took the process a stage further, especially when microscopic formats became a way for pupils of the typographical schools of the time to display their skill.

Paper-making techniques also evolved and added complications. In response to the request for small sheets of an appositely watermarked quality paper, for the purpose of letter-writing, special double-moulds were constructed, which made simultaneously two small sheets. Deciding what to call the format in these cases is never straightforward, but they remain exceptions that do not invalidate the general rule.

The truly big complication of course comes with the appearance of wove paper from 1757 onwards, since the helpful wire and chain-lines that play such a large part in deciding format promptly disappear [15]. Nevertheless, if wove paper made at the vat is used in a printed book, every effort should be made to determine the correct format. Early wove paper shows irregular striations in correspondence with the ribs underneath the mesh; once the experimental phase was over, watermarks were again attached to the surface and by their placing, especially the fact that the alignment is with the long edge, make it possible to determine format.

One reason for the relatively slow introduction of wove was the greater expense, not only in terms of making the mould, but also because the work at the vat was slower, since the water drained through the mesh less quickly. A consequence of this increase in cost is the variance in prices when an edition was printed with distinct print runs, one on laid and one on wove: for instance, the second edition of the Tragedie of Vittorio Alfieri, published in Paris in six volumes in 1788-89, was advertised as “Prix 48 livres les six volumes en feuille. Les copies en papier vélin, 100 livres”, or more than double; in Milan in 1827 the first edition of Manzoni’s Promessi sposi offered copies on laid at 12 lire, while those on wove were priced at 20 lire [30]. This fact means that, if there is some difficulty in deciding a format in wove, another copy may exist printed on laid, in which the solution is more simply diagnosed.

With the arrival of mechanical paper-making at the beginning of the Nineteenth century, in which the sheets are cut from a continuous roll, the concept of format becomes improper and redundant [16]. It is nevertheless always useful, in the case of a printed book, to apply paper analysis in order to discover the imposition of the typographical forme, but this operation should never be confused with the format derived from the sheet printed at the vat.

The difficulty, if anything, is to decide between wove paper made at the vat and mechanical paper made on a Fourdrinier or on a cylinder machine, since in appearance the two are very similar. One simple test, with loose sheets of paper, is to place it on a damp cloth and to allow it to absorb moisture. If all four edges rise, it is vat-made; if only two, due to the alignment of the fibres, it is mechanical. Of course this sort of experiment is frowned upon in most major libraries and archives, so the alternative is to scrutinise the paper with care. Up to about 1850, if the paper is watermarked, it is almost certainly vat-made. In 1836 a dandy-wheel was introduced for mechanical paper-making machines, which left an imprint on the sheet a second or so after it had formed. It was not possible, however, to position this with the same accuracy as in hand-made paper, until somebody had the idea of punching holes in the continuous sheet to act as a guide in the subsequent printing process. This expensive procedure was nevertheless reserved mostly for bank-notes, share certificates, and other documents that had to be forgery-proof.

What most often betrays mechanical paper is the seam that resulted from the two ends of the length of wire being sewn together. If a bibliographer has the patience to search through a certain number of copies of the same book, which it is believed is on mechanical paper, sooner or later the seam will reveal itself. In some instances, when the net began to suffer wear and tear, repairs were made to the same, in the form of stitching or small patches attached to the mesh, which in turn leave distinctive signs on the surface of the sheet.