Laser cleaning studies for the removal of tarnishing from silver and gilt silver threads in silk textiles

In the case of silk, previous studies indicated that the minima possible alteration occurs upon irradiation in the visible spectrum (at 532 nm). In contrary, ultraviolet (UV) light will decrease the degree of polymerisation and thereby will cause loss of physical strength, while infrared (IR) light results into yellowing. The changes initiated by the laser treatment will catalyse continuous physiochemical changes in the silk fibres. (Belli et al. 2006, Reichert 1998, Lerber et al. 2005) and thus it is essential to avoid them to the most possible extent.