AP: The term "codex" (lat. codex) refers to the development of "books" in literary history, as opposed to scrolls. Both were written on papyrus. A codex is ultimately the book format as we know it today, which replaced the use of the scroll. These are also referred to as a "manuscripts" because they are written by hand. This codex, which features the Gospel of Judas, is approximately 30 cm tall by 15 cm wide. It is written on papyrus, which was a primitive sort of paper; strands of the papyrus plant were layered and interlocking, horizontally and vertically on each side of the sheet, and then pressed. Egypt produced more papyri than other nations. They were famous for it. From Egypt it was exported to the rest of the Roman empire. Papyrus was used for many centuries, until it was totally replaced with another type of material, namely parchment. Parchment was already in use, but it became more popular during the Middle Ages. This type of material is made of animal skin that is tanned in a special way that makes it suitable for writing.
The codex with the Gospel of Judas actually had its original leather binding. It is severely damaged, but still there. This format of the codex is common to other early codices, which are usually rectangular in shape and elongated. At present, there are thirty-three pages. In some cases, those pages are very fragmented. With some, all that remains of the original is the middle of the top margin of the page showing the Greek page numbers (i.e., Greek letters as numerals). There is but a single column of text, averaging some 26 lines per sheet.
When we look at the codex, there are a number of features that we can analyze as we attempt to assign it a date. Usually these features are complementary. We can look at the material that is used, such as the papyrus, the type and style of the writing and calligraphy used, drawings or art on the sheets, the type of ink, etc. All of that gives us some idea for the date. Beyond that, we look at the actual content of the text (i.e., what it says). When books are written or published today, we have things like contracts and dates on copyright pages, etc. Things like this weren't really assigned to texts of antiquity. When we open up a book today, things just aren't the way they were. Only on occasion would a scribe write the date of his work at the very end of the text he was copying. And scribes didn't do that during the time period in which the codex with the Gospel of Judas was written.
Paleographically speaking (i.e., examining the style of writing, as well as the type or format of a codex), we know it was written in the fourth century A.D. Carbon dating has confirmed this as well. Why, you ask, did they carbon date it? No doubt to rule out any possibility of falsification, which, in the eyes of any scholar, is checked at first visual inspection. Carbon-14, which is a very expensive test, gives us a range around A.D. 280 to 340. An analysis of the ink also confirms this. Therefore, it seems obvious that this text was copied in a period that runs from the end of the third century to the beginning of the fourth. But it should be noted that the original text, which is not preserved for posterity, was written in the Greek language and already existed in A.D. 180, when Irenaeus mentions it. The Gospel of Judas, in the form in which we know it, is a translation into Coptic, copied in the fourth century. But the Greek text was written at least a century and a half before.