Multispectral imaging reveals faded text of Novgorod birch bark letters

Scientists of the National Research Center (SIC) "Kurchatov Institute" together with colleagues from the Institute of Archeology (IA) of the Russian Academy of Sciences conducted the first comprehensive analytical study of Novgorod birch-bark manuscripts written in ink. With the help of digital visualization methods, specialists were able to read fragments of faded text, determine the elemental composition of ink and birch bark. The results of the research were presented at the 7th European Conference on Neutron Scattering held on July 1-5 in St. Petersburg.

Credit: Institute of Archeology of the Russian Academy of Sciences

"Analytical diagnostics of objects of art and cultural values is becoming increasingly popular in modern interdisciplinary research. In our new work we have applied a non-destructive natural-scientific approach to the study of written objects of cultural heritage", said one of the authors of the study, a leading researcher of the laboratory of natural-scientific methods in the humanities of the Kurchatovsky complex of the NBIKS, Evgeny Sozontov.

Researchers have studied unique samples of the written culture of ancient Russia, the Novgorod birch-bark letters, the texts of which are believed to be written in ink. The Novgorod collection of manuscripts on birch bark has only three such documents: No. 13 (second quarter of the 15th century), No. 496 (second quarter of the 15th century), and No. 1089 (second half of the 14th century). However, document No. 13 is now considered lost. Scientists have analyzed the elemental composition of the assumed ink and birch bark letters Nos. 496 and 1089. With the help of multispectral photography method it was possible to see hidden fragments of faded and poorly readable text.

Birchbark letter No. 496 [Credit: Institute of Archeology of the Russian Academy of Sciences]

"Imaging was carried out with a specially prepared camera without a low-frequency filter, which made it possible to capture the reflected infrared light in the range of 940-1100 nm and to get images of visible luminescence when illuminating the letters with ultraviolet light", said one of the authors of the study, a researcher of the PaleoArt Center of the Institute of Archaeology of the Russian Academy of Sciences, Alexander Pakhunov.

As a result of the study, scientists have discovered that the texts on birch bark are indeed written in ink. Specialists determined their composition, and then continued digital processing of the image, which further strengthened the contrast between the background and the text.

Birchbark letter No. 1089 [Credit: Institute of Archeology of the Russian Academy of Sciences]

"Letters on the letter No. 496 became more clearly readable on the images in the reflected infrared rays, which confirms the assumption of its execution with soot ink. To visualize the text of letter No. 1089, it proved to be effective to photograph the visible luminescence with the subsequent enhancement of colour contrast. At the same time, the photos in the infrared range did not read the letters more clearly, which indirectly confirmed the absence of soot in the ink," said Alexander Pakhunov.

Experts also established that the characters on the birch bark letters were written with a wide (~1mm) brush edge. According to researchers, this is the first comprehensive analytical study of Novgorod birch-bark letters written in ink.

The first birch bark letter was found in Veliky Novgorod in 1951. Archaeologists believe that about 20 thousand birch bark letters from the XI-XV centuries lie hidden beneath Veliky Novgorod and that only 5-6% have been extracted so far.

Source: НИЦ Курчатовский институт [trsl. TANN, July 20, 2019]