*3.7. Red Pigments*

Spectra recorded by FORS on red areas showed the typical sigmoid shape that characterises the reflectance spectra of warm hues within the visible region. For these hues, the wavelength associated to the point of inflection in the reflectance spectrum may be indicative of a specific pigment [24], though this spectral feature could shift depending on the concentration of the pigment or if an achromatic colourant is added. With regards to the FORS spectra recorded on red areas of the *Book of Hours* (both miniatures and floral decorations on page borders), two main groups of spectra were observed. These two groups can be clearly distinguished by the different position of the inflection point of the sigmoid-shaped portion of the spectra (Figure 7). In one group, this feature was observed at 600 nm, whereas in the other group it occurred at a significantly lower wavelength (565 nm).

**Figure 7.** Selected FORS spectra representative of the two groups of spectra collected from red areas. Red line: spectrum obtained from the red vest of one of the Magi in the miniature on f. 31v (Figure 1e); blue line: spectrum obtained from the red acanthus on the upper part of f. 1v. The inflection points suggest the presence of red lead in the miniature and vermilion in the decoration on page borders.

These results suggested that two different pigments were used for reds: cinnabar or vermillion (HgS; it is not possible to distinguish between the natural and the synthetic version) and minium or red lead (Pb3O4), respectively. Both XRF and micro-Raman analysis confirmed the presence of these pigments. In fact, the XRF analysis revealed intense Pb signals in those areas in which the FORS analysis suggested the presence of red lead; moreover, the micro-Raman spectra of this pigment (with characteristic signals at 120, 150 and 550 cm−1) were recorded from red particles in the same spots. The presence of cinnabar/vermillion was confirmed both by the occurrence of mercury, detected via XRF, and by the characteristic micro-Raman spectrum, i.e., a strong band at 254 cm−<sup>1</sup> with a weak shoulder at 280 cm−<sup>1</sup> and a less intense band at 340 cm<sup>−</sup>1.

No red lead was detected in the decorations on the page borders and in the red letters throughout the written text, where only vermillion was used to paint red. This is consistent with a procedure involving another artisan with a different palette who decorated these parts of the manuscript. The hypothesis of a different artist working at the page borders, a less important part of the decoration, is more than reasonable if we consider that usually the decoration of a manuscript was more of a group work, in which the most important artist devoted himself to the most important aspects, namely the main miniatures.
