Test measurements on a secco white-lead containing model samples to assess the effects of exposure to low-fluence UV laser radiation

作者：Raimondi Valentina^*; Andreotti Alessia; Colombini Maria Perla; Cucci Costanza; Cuzman Oana; Galeotti Monica; Lognoli David; Palombi Lorenzo; Picollo Marcello; Tiano Piero

来源：Applied Surface Science, 2015, 337: 45-57.

DOI：10.1016/j.apsusc.2015.02.062

• UV laser irradiation
• Pigments
• Wall paintings
• Laser induced fluorescence
• Lead white
• Binders

Laser-induced fluorescence technique is widely used for diagnostic purposes in several applications and its use could be of advantage for non-invasive on-site characterisation of pigments or other compounds in wall paintings. However, it is well known that long-time exposure to UV and VIS radiation can cause damage to wall paintings. Several studies have investigated the effects of lighting, e.g., in museums: however, the effects of low-fluence laser radiation have not been studied much so far. This paper investigates the effects of UV laser radiation using fluences in the range of 0.1 mJ/cm(2)-1 mJ/cm(2) on a set of a secco model samples prepared with lead white and different type of binders (animal glue and whole egg, whole egg, skimmed milk, egg-oil tempera). The samples were irradiated using a Nd:YAG laser (emission wavelength at 355 nm; pulse width: 5 ns) by applying laser fluences between 0.1 mJ/cm(2) and 1 mJ/cm(2) and a number of laser pulses between 1 and 500. The samples were characterised before and after laser irradiation by using several techniques (colorimetry, optical microscopy, fibre optical reflectance spectroscopy, FT-IR spectroscopy Attenuated Total Reflectance microscopy and gas chromatography/mass spectrometry), to detect variations in the morphological and physico-chemical properties. The results did not point out significant changes in the sample properties after irradiation in the proposed range of laser fluences.

• 出版日期2015-5-15