Portable chemical imaging technology is a powerful analysis tool. It allows, for example, to reveal the secrets of ancient Egyptian paintings. It finds unsuspected hidden details, according to a study published in the journal PLOS ONE.
Ancient Egyptian paintings are often thought of as having a standardized form of production. They were the result of highly formalized workflows that produced skilled works of art. However, most studies of these paintings and the process that created them take place in museums or laboratories.

Changes in the paintings
The study is led by Philippe Martinez, Sorbonne University (France). It is in collaboration with colleagues at the University of Liège (Belgium). They use portable devices to obtain chemical images of paintings in their original context. This makes it possible to analyze the composition and layering of the painting. They are thus able to identify the alterations made to ancient paintings.
Two paintings were analyzed in detail, both located in tomb chapels in the Theban necropolis. This is near the Nile River. They date from the Ramesid period. In the first painting, the researchers were able to identify alterations in the position of the arm of a figure. But the reason for this relatively small change is uncertain.
In the second painting, analysis uncovered numerous adjustments to the crown and other royal objects depicted in a portrait of Ramesses II. It is a series of variations related to some change in symbolic meaning over time.

Outstanding secrets
These types of alterations to paintings are believed to be rare in this type of art. Researchers suggest that these findings require further investigation.
Many questions remain about the reasoning and timing of the observed alterations. Some of these may be resolved with future analyses. This study also demonstrates the usefulness of portable chemical imaging technology. It is of great help in studying ancient paintings in situ.
“These findings clearly call for a systematized and more thorough inspection. The secrets of Egyptian paintings have yet to be revealed,” the authors conclude.