January 29, 2021

Abstract:

Numerous severe shocks throughout the Middle Ages led to the death of a huge array of written sources. The degree of preservation of the corpus of ancient Russian manuscripts, which preserved the thousand-year intellectual and artistic heritage of Russia, is extremely small: tenths or hundredths of a percent is a debatable question. A significant part of them, having undergone external adverse influences, have come down to us in a damaged state - with extinct or specially destroyed texts and with great losses in the pictorial layer of miniatures. Considering that the probability of the appearance of new ancient book monuments is close to zero, then the relevance of increasing the information content of such sources stored in our museums for the historical study of the past centuries becomes incredibly high.

Thanks to the cooperation of specialists from the Department of Manuscripts of the State Historical Museum and IKI RAS, it became possible to restore some of the unique medieval monuments from the funds of the Museum. The use of natural science methods in their research focused on multispectral photography and the subsequent use of digital and mathematical methods for processing and analyzing its results. This method has one indisputable advantage - the equipment necessary for operation is budgetary and mobile, which makes it one of the few available natural science methods in the conditions of work in the Museum's depository.

In general, the same problems arise before the curators and medievalist researchers in different repositories, therefore the approaches found as a result of our work are probably universal. Some problems are solved with one multispectral survey without additional software processing. Shooting in the infrared range allows visualizing the extinct organic ink of Egyptian papyri, preparatory drawings for a number of miniatures, watermarks of medieval paper under iron-gallic ink, the original musical score of P.I. Tchaikovsky under the later single and double gluing, and also allows you to separate some of the later renovations, marked with carbon ink, in the ancient Byzantine painting of miniatures of the middle of the 9th century. Shooting in the UV range is good for visualizing faded, erased, dirty texts and drawings made with iron-gallic ink. The additional use of different shooting angles and lighting (raking light) made it possible to restore the almost completely extinct lifetime portrait of Ivan the Terrible, made in the technique of embossing on the skin on a tray tsarist copy of the first printed apostle Ivan Fedorov in 1564. More complex cases (almost completely washed out ancient Glagolic and Greek palimpsests filigree coated with soot ink) require specially designed programs. One of the most promising methods is the use of neural networks to reconstruct the lost fragments of the miniature painting layer. This objectively makes it possible to restore an ancient monument of art without introducing any updates to the original, and thus comes closer to the original intention of its creator.