Evaluation of laser cleaning for the restoration of tarnished silver artifacts

•Cyclic application of Q-switched Nd:YAG laser cleaning induces irreversible changes on pure silver.•Laser cleaning using Q-switched Nd:YAG laser at 1064nm induces loss of material and color changes.•Laser cleaning using Q-switched Nd:YAG laser at 532nm seems the most appropriate for cleaning sterling silver objects. In this study we evaluate the laser cleaning of tarnished pure and sterling silver substrates using a nanosecond Q-switched Nd:YAG laser at 1064, 532 and 266nm. To assess the effects associated with cyclic laser cleaning treatments, several cycles of tarnishing followed by laser cleaning were applied on silver coupons that were characterized by gravimetry, colorimetry, scanning electron microscopy, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. According to the obtained results, none of the three wavelengths is recommended for laser cleaning of pure silver objects, while for sterling silver artifacts, the visible laser wavelength of 532nm seems the most appropriate.