In studying cross-sections of green paint layers, it is sometimes ascer tained that the green is either covered with or embedded in a brown-colored substance. In an attempt to determine whether this is to be attributed to discoloration of the green paint, the eventual presence and the exact location of copper in this brown substance were investigated. The Scanning Electron Microscope with x-ray Microanalyser Accessory was used. Some results of preliminary tests are given in order to indicate the possibilities and the limitations of this method for this purpose.