@misc{10481/108428,
year = {2025},
month = {11},
url = {https://hdl.handle.net/10481/108428},
abstract = {Laser cleaning of soiled wall paintings is a conservation practice that has been adopted for decades. However, the increasingly widespread availability of laser technology highlights the need to optimize the
choice of laser systems and, consequently, the parameters used on a case-by-case basis. In this study,
three Nd:YAG lasers (1064 nm) with different pulse durations were tested: a short free-running system
(110 μs), long Q-switched system (100 ns), and Q-switched (8 ns). These lasers were tested on tempera
painting mock-ups made of one pigment (i.e. malachite, azurite, lead white, orpiment, or cinnabar) mixed
with an organic binder (i.e. egg yolk or rabbit glue) applied to a lime mortar. Each laser was also evaluated in tablets composed solely of one pigment. The reference and irradiated temperas were studied using
stereomicroscopy, spectrophotometry, attenuated total reflectance Fourier transform infrared spectroscopy
(ATR-FTIR), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The
pigment tablets were also analyzed with micro X-ray diffraction (μXRD).
All samples suffered blackening after laser irradiation, the intensity of which depended on the nature
of the pigment and the binder. Overall, pigment susceptibility was broadly comparable across the three
pulse-duration lasers. Cinnabar exhibited the highest level of susceptibility, followed by copper carbonates and orpiment, while lead white proved to be the least affected pigment. The binders exhibited a
protective effect on the pigments, although this effect was more intense in egg yolk paintings. Regarding
pulse duration, it was found that at low fluences, the laser with the longest pulse duration generated
the lowest color changes, while at high fluences, this same laser generated the greatest impact on the
temperas. Physical effects were observed in the samples (mineral melting and binder loss), though these
were not proportional to the intensity of the blackening.},
organization = {MICIU/AEI/10.13039/501100011033 / ERDF–EU (Proyecto PID2021-123395OA-I00)},
organization = {MICIU / ESF+ (Beca PRE2022-105106)},
organization = {Xunta de Galicia / Unión Europea – FSE+ Galicia 2021–2027 (Contrato Predoctoral ED481A-2023/086)},
organization = {MICIU / ESF “Investing in your future” (Proyecto RYC2020-028902-I)},
publisher = {Elsevier},
keywords = {Pictorial heritage},
keywords = {Heritage conservation},
keywords = {Laser cleaning},
title = {Influence of pulse duration on the effects induced by three Nd:YAG lasers operating at 1064 nm to tempera paintings mock-ups},
doi = {10.1016/j.culher.2025.10.023},
author = {Andrés-Herguedas, Laura and Jiménez Desmond, Daniel and Ricci, Chiara and Zenucchini, Francesca and Rivas, Teresa and Cardell Fernández, Carolina and Pozo-Antonio, José Antonio},
}