Samples were also examined by Interrogativo-Ray fluorescence spectroscopy by means of a Surface Filmato instrument supplied by Assing

Samples were also examined by Interrogativo-Ray fluorescence spectroscopy by means of a Surface Filmato instrument supplied by Assing

The XRF spectra were obtained with the following experimental conditions: Mo tube operating at 25 kV voltage and 300 ?A beam current; scan time 120 s; distance 95 mm.

Regarding wood samples, thin sections were obtained according puro the anatomic wood directions and described following the IAWA list of microscopic features for hardwood and softwood identification [12, 13]. Thin sections of the wood sample were examined under a Polyvar 100 optical microscope equipped with per PIXeLINK digital camera.

Temperature (T) and relative humidity (RH) values have been recorded through a digital luvfree giorno logger Elenco 177-H1 model. The scadenza logger has been calibrated and hanged on the northern wall of presbytery. Data have been recorded from 26 of July sicuro 8 of September and then elaborated by Excel programma puro obtain maximum, minimum, average values and canone deviation throughout the analysed period. The temperature and relative humidity successo and failure indexes were also calculated and showed sopra the tolerance matrix, durante order onesto obtain a synthetic expression of the results [14, 15].

Painting material analysis

Stratigraphic and chemical analysis revealed the presence of superimposed layers constituted by several different materials. For this kind of artefacts it is usual preciso find many superimposed painted layers paio sicuro a continuous usage of the object that has got verso demo-ethno anthropological significance. Per Figure 5 the ciclocross sections of the painting samples are showed. The white layer characterized by an intense yellow fluorescence is constituted by zinc white verso pigment widely used starting from 19 th century. According preciso this result it is possible preciso assess that the surface painted layer was certainly applied during the 19 th or later. The painted layers were applied over gypsum and glue, as revealed by FTIR analysis and UV fluorescence examination of the ciclocross sections. Glue exhibits verso light blue fluorescence under UV lighting. At last, per sample ASN2 and ASN4 an orange UV fluorescence can be observed. This fluorescence can be associated to the presence of shellac, verso natural resin often used with the function esatto isolate the priming or the support before applying the painted layers or the setting respectively.

Results and tete-a-tete

Microphotographs of samples ASN1 (Verso, B), ASN2 (C, D), ASN4 (E, F) and ASN5 (G, H), under reflected light (Per, C, Anche, G) and UV fluorescence (B, D, F, H).

As example of infrared analysis result, the FTIR spectrum of sample ASN1 is showed (Figure 6). The main compound is gypsum with the bands at: 3485 cm -1 , 3400 cm -1 , 1621 cm -1 , 1111 cm -1 , 684 cm -1 and 609 cm -1 . Moreover, calcium carbonate (bands at: 2513 cm -1 , 1797 cm -1 , 1431 cm -1 and 875 cm -1 ), verso siccative oil (bands at 2924 cm -1 , 2854 cm -1 , 1737 cm -1 and 1713 cm -1 ) and iron oxides (peak at 528 and 470 cm -1 ) are present. In sample ASN4, also the bands associated onesto proteinaceous compounds have been detected, mediante particular the 1540 cm -1 peak paio puro amide II [16, 17].

XRF analysis revealed the presence of zinc sopra all the examined samples but also of lead (Table 2). According puro this result we can say that the white layer, visible per sample ASN2 and ASN5 ciclocross sections was probably made of lead white. This painting was realized previously con respect sicuro that made of zinc white. The presence of iron suggests the use of red, yellow and brown ochre. The green grains visible durante the ciclocross section of sample ASN2 are made of verso copper based pigment. Sample ASN3, defined as gilding, contains zinc and copper suggesting the presence of brass powder used preciso imitate gold. Arsenic is per component of the alloy. The use of brass preciso imitate gold was particularly diffused during the 18 th century, especially sicuro produce objects employed on the occasion of popular and traditional festivities .

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