Materials (Basel) 2019 Nov 21;12(23). Epub 2019 Nov 21.
Istituto di Fisica Applicata "Nello Carrara", Consiglio Nazionale delle Ricerche, v. M. del Piano 10, 50019 Sesto Fiorentino (FI), Italy.
Here, a systematic study in order to assess the potential of THz time domain reflectometry for measuring the thicknesses of overpaint layers applied on original gilded surfaces was carried out. The work is part of a thorough characterization campaign, which is going on at the Rijksmuseum for addressing the conservation problems of a set of 19th century gilded picture frames on which heavy coatings were applied in previous undocumented restoration interventions. To perform such non-invasive thickness measurements, an analytical protocol based on Gaussian fits of the THz pulse-echo temporal profiles was optimized through the preparation of suitable technical samples and the comparison with direct thickness measurements. Read More