The author compares current scientific data from the sistine chapel with those obtained in 1936, 1938 and 1941 by s. Sica and v. Federici, who identified the composition of salt efflorences and of the animal glue used in previous restorations. The present examinations include pigment analysis (using atomic absorption spectrophotometry, infrared spectrophotometry, thin-section chromotography, and liquid chromotography) and colour sections of the fresco layers. The various components of the fresco are described in general terms, and the pigments are listed. The composition and use of the solvent ab 57, used for the cleaning are described a list of sample areas with specific result is appended.