A color analysis of the Brancacci Chapel frescoes

About one hundred significant spots (area = 0.5 cm2) that were homogeneously colored were selected on the frescoes 'Resurrection of the son of Teofilo,' 'Saint Peter in pulpit,' and 'Saint Peter heals invalids by his shadow' in the Brancacci Chapel (Chiesa del Carmine, Florence). The reflectance spectra of these spots were recorded before and after restoration with the use of an external integrating sphere, which was connected through optical fibers to a UV/visible spectrophotometer, and the data were stored in a personal computer. Spectrophotometric investigations were also performed on small samples of frescoes, which were appropriately prepared, in a laboratory, with pure pigments. The results we obtained are discussed in the light of our main purposes: (1) to achieve nondestructive indentification of pigments; (2) to help create time-unalterable color archives; (3) to establish a method for monitoring eventual color changes; and finally (4) to obtain useful information for the fields of art restoration and art history.