When trying to understand the process of making small format papyrus codices, it is sometimes tricky to figure out how the papyrus bifolia were cut from the roll. For books that are more tall and narrow, like the Nag Hammadi codices, it is generally clear that the bifolia were cut from a roll with a height equal to that of the bifolia. But for codices whose height is smaller than that of the typical roll, there are other possibilities. Some of the newly available images of the Bodmer nicely illustrate one of them. The designations P.Bodmer XII and P.Bodmer XIII refer to two texts in the so-called Bodmer Composite Codex. P.Bodmer XIII is the paschal sermon of Melito in Greek, and P.Bodmer XII is a short hymn copied on the back of the last page of Melito’s sermon (for a full discussion of the make-up of this codex, see my earlier discussion). The original editions of these papyri provided black and white plates of both the last page of Melito’s sermon and the hymn known as P.Bodmer XII. The most obvious oddity on the leaf is the area of erasure below the hymn:

In addition to offering us a better view of the erased area, the new images allow us to see more clearly other aspects of this leaf, namely the fiber orientations:

Leaf containing the last page of P.Bodmer XIII (left) and the lone page of P.Bodmer XII (right); image source: Bodmer Lab

And the fiber orientations are quite curious. On the recto (Melito’s sermon), the top half of the page is written along the fibers, but the lower half of the page is written against the fibers:

Detail of last page of P.Bodmer XIII showing shift from horizontal fibers (top) to vertical fibers (bottom); image source: Bodmer Lab

The reverse is true of the verso (P.Bodmer XII), on the upper half of the page, the text is written against the vertical fibers, but on the lower part of the page, the text is written along the fibers (the break happens in the center of the least line of the hymn):

Detail of P.Bodmer XII showing shift from vertical fibers (top) to horizontal fibers (bottom); image source: Bodmer Lab

This point was actually noted by Rodolphe Kasser and reported by Aland and Rosenbaum in 1995 (Repertorium der griechischen christlichen Papyri II: Kirchenväter-Papyri, p. 377, note 12):

Kasser [hat] auf ein merkwürdiges Phänomen aufmerksam gemacht: Die Recto-Seiten ΝΓ und ΞΔ haben im oberen Drittel einen Faserverlauf quer zur Schrift (sind also in diesem Bereich eigentlich Versos), während die Verso-Seiten ΝΔ und ΞΓ nur in den unteren zwei Fünfteln der Seite wirkliche Versos sind (auf den oberen Fünfteln läuft der Text parallel zur Faser). . . . Zu erklären ist diese Merkwürdigkeit wohl dadurch, daß das (quer zur Laufrichtung der Industrierolle geklebte) Protokollon zur Herstellung der foll ΝΓ/ΝΔ bzw. ΞΓ/ΞΔ (die also ursprünglich ein Doppelfol gebildet haben müssen) mitverwendet wurde.

So, both this leaf and the other half of the bifolium of which it is a part (pages ⲛⲅ and ⲛⲇ) have this curious fiber pattern, indicating that the bifolium was cut from the protokollon, or first sheet, of a papyrus roll, which generally has the opposite fiber orientation from the rest of the sheets that make up a roll:

Model of the beginning of a typical papyrus roll, showing fiber orientations

This means that the bifolia for this codex may have been cut from the roll in pieces that were the intended height of the bifolia, resulting in horizontal rather than vertical kollēseis (joins where the sheets of the roll overlap):

Model of papyrus roll being cut into bifolia for a square-format codex by intended height of the bifolium

The bifolia of other codices of a similar small square format were sometimes cut from the roll in a rather different way: They were cut in pieces that matched the width of the intended bifolia and then split in half vertically. This is the way that the bifolia of Berlin Akhmimic Proverbs Codex (Staatsbibliothek zu Berlin, Ms. or. oct. 987, LDAB 107968) were prepared, according to the analysis of Hugo Ibscher:

Model of papyrus roll being cut into bifolia for a square-format codex by intended width of the bifolium

As a result, the leaves of the Berlin Proverbs codex have vertical kollēseis. This codex also employed the first sheet (protokollon) of the rolls so that three leaves show both vertical and horizontal fibers, but in this case, the dividing line is vertical rather than horizontal, as can be seen on page 30 of the codex:

Berlin Akhmimic Proverbs Codex (Staatsbibliothek zu Berlin, Ms. or. oct. 987), page 30; image source: Staatsbibliothek zu Berlin

The change in fiber directions can be seen quite clearly if we zoom in:

Detail of page 30 of the Berlin Akhmimic Proverbs Codex, showing the shift from vertical fibers (left) to horizontal fibers (right), indicating that the bifolium was cut from the protokollon of a roll; image source: Staatsbibliothek zu Berlin

It is also conceivable that the bifolia of a small-format square codex could be prepared by a combination of these methods, first cutting bifolia in the manner of the Berlin Proverbs codex until the protkollon is reached. If the remaining portion of the roll is not long enough to match the breadth of the intended bifolium, a single bifolium might still be salvaged by cutting a piece to match the height of the intended bifolium, which might incorporate a portion of the protokollon.

Looking at this pair of codices together is a good reminder that the horizontal fibers of the leaves of smaller square codices might not necessarily have been the horizontal fibers of the roll from which the bifolia were cut.