Holographic testing of possible mechanical effects of laser cleaning on the structure of model fresco samples

• Custom-made model fresco samples with artificial encrustation were laser cleaned.
• The uniformity of samples was checked by mechanical tests.
• Laser cleaning did not cause any holographically detectable damages to samples.
• Consolidation of the samples improved the laser cleaning efficiency.

Custom-made fresco samples covered in artificial crust were laser cleaned, and the consequent mechanical effects were tested with digital holographic speckle pattern interferometry (DHSPI). DHSPI proved capable of detecting the structural alterations in the fresco. It was shown that the laser cleaning process caused no structural damage to the intact samples and has not worsen the damages in case such were originally present. Quantitative evaluation of the fringe patterns revealed that the potential risk of laser cleaning is negligible on the mechanical structure of the frescos. Consolidation with Remmers KSE 300 has improved the laser cleaning efficiency in the UV.