Known for his frescoes using illusionist perspective, Pozzo's most dramatic work can be found in Rome in the painting of the dome, apse, and ceiling of the Church of S. Ignazio (1685-1694).
It took four years, he said in an e-mail, to work on everything from the basement floors to the ceiling frescoes, using seven mules to haul building materials up the steep hillside.
only colorimetric data (that is the L*, a*, b* CIELab parameters), obtained by measurement in situ using Minolta software was possible to compare with those ones obtained by similar colorimetric measurements on standard frescoes, using chemometric methods (see Table 6).
Medieval frescoes used to cover the entirety of the church's interior, though only some 70 fragments survive until today.
On the other hand, in order to characterize and identify a standard fresco prepared using an unknown black pigment, thermogravimetry, Raman microspectroscopy and colorimetry were applied, while to identify the in situ Roman fresco, it was possible to apply only colorimetry and reflectance spectroscopy.
(b): HCA representation of CIELab colorimetric data of all standard frescoes fabricated using standard black pigments and unknown black pigment of old roman fresco (i.e. black-studiolo).
Table 4 Colorimetric (CIELab) data of all standard frescoes fabricated using standard black pigments and the considered unknown black pigment (i.e. black-ivory- VS)).
Table 5 Raman microspectroscopy data of standard frescoes fabricated using standard black pigments and the considered unknown black pigment (i.e. black-ivory- VS)).
However the wavelength differences of Raman peaks of different black pigments we studied were found to be in practice not always well obvious (Figure 3) [6]. Figure 3 Raman spectroscopy curves of standard frescoes fabricated using standard black pigments and the considered unknown black pigment sample (i.e. black-ivory- VS)).
Mora and Philippot state that the fresco painting technique developed in the Italian Trecento was an improvement in relation to the fresco technique used in Roman, Byzantine and Romanic times, as it allowed the execution of complex compositions by dividing the wall into giornate and provided better qualities of surface and texture [108].
