Surprising ingredient discovered: lead apparently already ensured that writing in some ancient Egyptian inks dried quickly, according to an analysis of almost 2000 year old papyrus writings. Previously it was assumed that the corresponding use of lead compounds goes back to painting in the 15th century, when these substances were used to harden oil paints more quickly.
Ink literally made history: the earliest examples of preserving human thoughts by applying ink to flexible materials come from ancient Egypt. The colored liquids became from about 3200 BC. Used to add characters to papyrus. This practice then shaped the whole of ancient Egyptian history up to the time of the Romans. There were two basic principles behind the use of color: black ink was used to write the main parts of the text, while red ink was often used to highlight headings, instructions, or key words.
What was in there
It is already known in principle that most inks are mainly made from the substances soot and ocher, which are mixed with a binder. In many cases, however, the exact recipes are unclear. As part of their study, the researchers led by Thomas Christiansen from the University of Copenhagen looked at the composition of red and black inks that were once used to write on papyri in the so-called temple library of Tebtunis. It is a facility that was used until the early 3rd century AD and is located 100 kilometers southwest of Cairo.
Thousands of fragments from a total of 400 to 500 manuscripts were discovered in the ruins. Today these pieces from the period AD 100 to 200 are in the Papyrus Carlsberg Collection at the University of Copenhagen. For the study, the scientists subjected the red and black inks on twelve papyrus fragments to a modern analysis process that enables detailed insights into the composition of the substances.
Lead accelerated the drying process
“Our analyzes of the inks on the papyrus fragments revealed previously unknown components of these red and black substances, especially of lead-based compounds,” says Christiansen. Co-author Marine Cotte of The European Synchrotron Radiation Facility in Grenoble continues: “We found that lead was added to both ink mixtures, not as a dye”. The researchers came to this conclusion because they did not find any lead compounds such as white lead or minium that would have to be present when using lead as a pigment. They therefore assume that the lead fulfilled a special function. It seems plausible that it acted as a so-called siccative – a substance that leads to faster hardening.
It was for this very purpose that lead was used many centuries later. “One of the challenges in Renaissance oil painting was getting the oil to dry in a reasonable amount of time,” says Cotte. “The painters realized that some lead compounds could be used as efficient dryers,” she explains. The researchers therefore believe that the Egyptians discovered at least 1,400 years earlier that by using these substances in their inks they could ensure that their papyri would not smear.
“The fact that the lead was not added as a pigment but as a dryer also leads to the conclusion that the ink had a very complex recipe and could not be made by everyone,” says Christiansen. “Based on the amount of raw material that was needed to supply a temple library like the one in Tebtunis, we suspect that the priests acquired them or that they were made in specialized workshops – similar to the paints used by the masters of the Renaissance was the case, ”says Christiansen in conclusion.
Source: University of Copenhagen, European Synchrotron Radiation Facility, specialist article: PNAS, doi: 10.1073 / pnas.2004534117