The article details the logic behind the use of two-dimensional, rising paper chromatography for determining the approximate age of wallpaintings up to an age of roughly 2000 years, when all traces of amino acids have generally disappeared. Apparently, the number of amino acids in the binding media drops sharply in the first 100 years from application and then more gradually for up to 2000 years. The author gives precise directions for laboratory tests, tells how the method was developed by sampling of murals on interior walls of churches, and how the author then applied the method for determining the age of rock paintings in South and Southwest Africa. He emphasizes that the method needs further refinement and that fundamental research needs to be undertaken for that purpose.