Since 2014, the Doerner Institut has been researching flesh tones in the network research project ISIMAT (Flesh tone and significance: The human image in panel painting in the Mediterranean area from 200 to 1.250 A.D). This interdisciplinary network research project is subsidized by the Federal Ministry of Education and Research (BMBF). Even if this topic may at first sight seem very specific, the mentioned period from 200 to 1250 A.D. comprises the evolution of panel painting. The panel painting has influenced our understanding of painting, with the images of humans and consequently the skin color of humans (flesh tones), counting among its most important tasks. But how were flesh tones painted? This question about the technical requirements, conditions and parameters of the origins of panel painting and its further development is researched by ISIMAT: art historians and specialists in art technology and documentary sources as well as scientists investigate a period of more than 1.000 years of the development of panel painting. For doing this, representative examples from the Ancient World as well as from Early and High Middle Ages in German museums, from churches in Rome and Florence as well as in Saint Catherine´s Monastery on Mount Sinai are examined with state-of-the-art methods.