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 identification 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.

Radioactive decay of nuclei by the emission of heavy ions of C, N, O, F, Ne, Na, Mg, Al, Si, and P isotopes (known as exotic decay or cluster radioactivity) is reinvestigated within the framework of a semiempirical, one-parameter model based on a quantum mechanical, tunnelling mechanism through a potential barrier, where both centrifugal and overlapping effects are considered to half-life evaluations. This treatment appeared to be very adequate at fitting all measured half-life values for the cluster emission cases observed to date. Predictions for new heavy-ion decay cases susceptible of being detected are also reported.

The restoration work of the frescoes in the Brancacci Chapel (Chiesa del Carmine, Firenze) offered us the opportunity of recording about one hundred reflectance spectra of selected areas on the frescoes before and after restoration. Our previous research was mainly devoted to pigment identification. In the present paper, color analysis is performed by computing chromaticity coordinates, purity, and dominant wavelength, starting from the reflectance spectra previously recorded. Afterwards, color difference between restored and not-restored fresco is evaluated and its distribution examined. The obtained results are then discussed in connection both to the causes which produced the color modification and to the possibility of performing electronic restoration on paintings.

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