TECHNART 2023. The International conference on analytical techniques in art and CH.

In May 2023, Daniel Jimenez Desmond participated in the International conference on analytical techniques in art and cultural heritage TECHNART 2023, celebrated in Lisbon (Portugal). He presented the poster entitled “Preliminary evaluation of nano-silica-based chromatic reintegration on frescoes”.

Wall paintings can suffer material loss in the form of lacuna when they are outdoor exposed, where conservator-restorers may have to carry out chromatic reintegrations that have to be weather-resistant. Nowadays, the most recommended binder for chromatic reintegration related to outdoor wall paintings is silica-based paint, that is a mixture of pigments with a mineral binder. Therefore, a study has been carried out through the elaboration of mock-ups aiming to analyse the physical compatibility between fresco paintings and their nano-silica-based chromatic reintegrations. In the conference, Daniel presented preliminary results related to the physical compatibility between both techniques and nice different pigments that were characterised by colour spectrophotometry, measurements of gloss, reflectance, roughness, and hydrophobicity and peeling test. Samples were also characterized by means of X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS).

Overall, major colour and gloss variations were observed between both techniques, and a cracked surface could be appreciated on all chromatic reintegration mock-ups. However, industrially manufactured pigments (19^th century onwards) presented more homogenous surfaces than those from natural origin. Mock-ups will soon be evaluated after one year exposure to natural environments to determine weather compatibility.