The analytical study of samples taken from the Carracci frieze provided information on original materials and technique as well as on past retouching and treatments which were responsible for obscuring the brightness of the original colors. The frieze is a true fresco painting without any addition in secco. The technique of Italian mural painting of the 16th century in comparison with that of previous periods is discussed, also taking into consideration technical investigations of other works and information given by antique treatises. The methods of the restorers of the past are also discussed.