In this work, the results of a detailed art technological investigation of the icon Last Supper from the Russian Memorial Church in Leipzig (Germany) are presented. The icons of the iconostasis of the church were made in the workshop of N.S. Emelyanov in Moscow in 1912. The investigation showed that the painter in principle technologically adhered to the traditional way of making icons. The panel is made of boards of lime wood with two crossbars on the reverse. The paint was applied to a chalk ground over a textile layer. The traditional iconographer’s palette was expanded by a few contemporary pigments. The binding agent is classic egg tempera. Originally, the layers of paint had an oil varnish (olifa). The main aim of the project VirtEx, introduced in this paper, is to expand existing methods with numerical material and structural models to be able to predict quantitatively the behaviour of wooden artefacts under loads due to climate changes as well as mechanical loads. The detailed art technological investigation provides the required data for the computer models. The numerical data can then be validated with technologically exact copies and replicas. In the introduction to the article, the current state of research on icon painting techniques is also outlined.