The technique of depicting a human face constitutes the most challenging part of icon painting. A comparison with <i>dolichnoe</i> painting of dresses, architecture background, and landscape, shows that human faces were executed in a more detailed and sophisticated manner; they had a greater number of modeling stages and paint layers. The faces seen in Byzantine and Russian icons look particularly complicated. Unlike them, wall and miniature painting were more frequently done using shorthand methods. However the painting procedure remained identical; in other words, it was layer-by-layer application. It is very difficult to investigate painting methods because they were masked and undetectable, which was consistent with the basic esthetic ideas of the Middle Ages: icons could not be created by man. The method of optic examination of painting layers with the aid of a binocular microscope has been developed to help a restorer to uncover the original and to discriminate between the ancient painting and many overpaintings.