## 4 Results
### Pigments and Dyes
#### 4.4.4 Red Pinkish and Flesh Hues  
PLM and ESEM -EDX investigations carried out on the red (sample GSM1) and pinkish (sample GSM2) hues of the _Martydrom of Saint Sebastian_ panel (Table S2) showed an underpaint layer composed of different amounts of vermilion, lead white and red lake particles. The overlapped glaze layer is composed of a red lake glaze with powdered glass particles found only in sample GSM1. The detection of the red lake by PLM and ESEM-EDX due to the high peak of Al [42], was confirmed in superficial layers by previous reflectance spectroscopy measurements [6]. The FTIR-ATR analysis of the pinkish layer of sample GSM2, in addition to the absorbances referable to lead white, detected the bands related to esters carboxylic acid, free carboxylic acids and lead carboxylates (\(\sim\)1540-1503 cm\({}^{-1}\)), indicating the use of an oily binder, which over time reacted with the Pb\({}^{2-}\) ions of the pigment. Proteinaceous material was detected too according to the band at 1645 and 1540 cm\({}^{-1}\), possibly related to egg binder added to vermilion or to the restoration compounds. According to PLM and ESEM/EDX, the flesh of Saint Sebastian (sample GSM6, Table S2) is composed of a double layer of lead white, vermilion and rare lead tin-yellow particles. The overlapped blood drop consists of red lake [43], lead white, calcium carbonate and powdered glass particles. In both samples, GSM1 and GSM6, the red layers showed FTIR-ATR spectra in which both stretching of CH\({}_{2}\)-CH\({}_{3}\) groups at \(\sim\)2925 and 2853 cm\({}^{-1}\) and stretching of carboxylates (COO\({}^{-}\)) around 1575 and 1458 cm\({}^{-1}\) are visible. No signals due to the anthraquinone compounds of the lake were detected, due to both the low concentration of the dye and the co-presence of peaks of other substances (mainly lipids and carboxylates) in the region of interest. Instead, a signal centered at 1036 cm\({}^{-1}\) was detected. It can be assigned to silicates and hydrated alumina, a component of the lake [51] (Figure 5). In the _Visitation_ altarpiece, stratigraphic observations of flesh hues showed a pinkish painting layer (60 \(\upmu\)m) based on lead white, vermilion, finely grounded glass particles (with a minimum size of 10 \(\upmu\)m), hematite, red lake and dolomite particles (sample SF1: Figure S8a-c, Table S3). FTIR-ATR attested the presence of lead white, esters of carboxylic acid and lead carboxylates indicating the use of an oily binder. PLM and ESEM-EDX investigations showed that in the shadow of St. Elisabeth's mantle, the underlayer (with an overall thickness of 228 \(\upmu\)m) consists of two layers of lead white mixed with red lake and colorless powdered glass (sample SF4: Figure S8c-f, Table S3). The overlapped glaze layer (of 85 \(\upmu\)m) is mainly rich in the red lake and powdered glass particles with their typical jagged edges. EDX analysis revealed Si, Ca, Na, Al, K, Fe and Mn. The FTR-ATR of the underlayer showed the presence of lead white, esters of carboxylic acid and lead carboxylates denoting the use of an oily binder. In the red glaze layer, FTR-ATR detected lead white and esters of carboxylic acid. In the [PERSON]'s brilliant red dress, the underlayer (55 \(\upmu\)m) is composed of vermilion, a small amount of lead white and colorless glass particles. The glaze layer (15 \(\upmu\)m) consists of red lake, vermilion, rare bone black particles and calcium carbonate according to EDX spectra (sample SF3: Figure S8g-i, Table S3). The FTIR-ATR spectrum of sample SF3 clearly shows peaks referable to lipids (2927-2852, 1731-1694 cm\({}^{-1}\)) and proteinaceous compounds (\(\sim\)3290 and \(\sim\)1650 cm\({}^{-1}\)). Conversely, sample SF4 showed two pink layers under the transparent red glaze, both containing lead white and small percentages of lake and glass powder particles. The FTIR-ATR analysis attests that the oily binder appears to be largely converted into lead carboxylates.