The controversy over the Sistine Chapel ceiling treatment is briefly reviewed. Instrumentational methods of examination employed by the Metropolitan Museum, the Louvre, and the National Gallery are mentioned. Infra-red reflectography is used, particularly to study northern Renaissance paintings. A scanning microdensitometer measures color wavelengths and digitalizes the measurements. High-energy ion beams are used for pigment analysis. Varnish requirements, autoradiography, and artificial aging are also touched upon. -- AATA