Nov. 10 (UPI) -- New X-ray images have revealed copper in the ink scrawled on 2,000-year-old Egyptian papyri fragments.
Until now, archaeologists thought Egyptian scribes used ink composed entirely of carbon-based ingredients until the fourth and fifth centuries AD. The latest findings -- detailed in the journal Scientific Reports -- suggest scribes began mixing copper into their carbon-based inks much earlier than previously thought.
The practice was apparently widespread, as X-ray microscopy images revealed copper in a variety of papyri fragments, hailing from different geographical regions and produced over a period of 300 years.
"The composition of the copper-containing carbon inks showed no significant differences that could be related to time periods or geographical locations, which suggests that the ancient Egyptians used the same technology for ink production throughout Egypt from roughly 200 BC to 100 AD," Thomas Christiansen, an Egyptologist at the University of Copenhagen, said in a news release.
The fragments surveyed in the latest study are part of the Papyrus Carlsberg Collection at the University of Copenhagen. Several of the fragments are sourced from the papers of Horus, an Egyptian soldier who kept a diary of sorts during his time at the military camp in Pathyris, a city near Thebes.
Other fragments belong to manuscripts recovered from the Tebtunis temple library, the only surviving institutional library of Ancient Egypt.
"None of the four inks studied here was completely identical, and there can even be variations within a single papyrus fragment, suggesting that the composition of ink produced at the same location could vary a great deal," Christiansen said. "This makes it impossible to produce maps of ink signatures that otherwise could have been used to date and place papyri fragments of uncertain provenance."
"However, as many papyri have been handed down to us as fragments, the observation that ink used on individual manuscripts can differ from other manuscripts from the same source is good news insofar as it might facilitate the identification of fragments belonging to specific manuscripts or sections thereof," Christiansen added.
Knowledge about the exact composition of ancient inks can help inform decisions about how best to preserve ancient papyri artifacts.