Tackling conservation challenges using erbium lasers: case studies at the British Museum

Pereira-Pardo, Lucia; Melita, Lucia Noor; Korenberg, Capucine

doi:10.1080/19455224.2019.1706591

Cited by 4 publications

(1 citation statement)

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“…Although the Er:YAG laser was successfully applied for varnish removal [23][24][25][26][27][28][29], to our best knowledge, there is limited study on the situation when pigments in pictorial layers are also sensitive to this laser. Besides, laser cleaning is thought to be intuitive, and controlled cleaning can be performed by simply changing the fluence or pulse duration of the laser beam based on the experience or skill of the operator.…”

Section: Introductionmentioning

confidence: 99%

Er:YAG Laser Cleaning of Painted Surfaces: Functional Considerations to Improve Efficacy and Reduce Side Effects

2021

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The restoration of paintings always involves the removal of darkened superficial layers, which are mainly due to dust deposition and aged varnishes. As cleaning is an irreversible and invasive treatment, physical methods (i.e., laser cleaning) instead of chemical ones are frequently suggested to reduce side effects on pictorial layers. Among the most employed laser systems, the free-running Er:YAG laser is considered very suitable for fine arts cleaning. This laser works at 2.94 μm, at which only –OH and –NH bonds in molecules are excited. This character can become a disadvantage when pigments with these functional groups are present. To understand the potential of the Er:YAG laser in such situations or in the presence of degradable pigments, the effectiveness of varnish removal from paintings prepared with egg yolk as the binder and cinnabar and lead white as the pigments were systematically investigated. Different cleaning conditions were used, and a hyperspectral sensor was innovatively used as a rapid, in situ and non-destructive technique to assess the effects of laser ablation, besides microscopic analysis. Though results obtained show all these pigments are sensitive to this laser radiation, satisfactory cleaning can be achieved without damaging the pictorial layer. The best cleaning conditions were 0.5 W of power (50 mJ and 10 Hz for energy and frequency), with 2-propanol as the wetting agent.

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Section: Introductionmentioning

confidence: 99%

Er:YAG Laser Cleaning of Painted Surfaces: Functional Considerations to Improve Efficacy and Reduce Side Effects

2021

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Successes and challenges in laser cleaning metal artefacts: A review

Bertasa

Korenberg

2022

Journal of Cultural Heritage

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Investigating the Potential of the Er:YAG Laser for the Removal of Cemented Dust from Limestone and Painted Plaster

et al. 2020

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A successful application of Er:YAG laser for the cleaning of a restored Assyrian relief sculpture from the British Museum collection is presented. Displayed in the gallery, the sculpture has darkened over time due to the natural deposition of dirt, in particular on restored parts. Since traditional cleaning methods have demonstrated to be unsuccessful, a scientific investigation was performed to identify the composition of the soiling and the materials used for the restoration. The analysis suggested the presence of gypsum, calcium oxalate, carbonates and alumino-silicates on the encrustation. The molded plaster, composed of lime and gypsum and pigmented aggregates, was likely prepared at the end of the 19th century to mimic the stone color. It was repainted with what was identified as a modern oil-based overpaint, applied to cover darkening during a second conservation treatment in the 20th century. Laser trials were first performed on small areas of the objects and on mock-ups to determine the critical fluence thresholds of the surface, investigated through visual examination and analyses using Fourier transform infrared spectroscopy (FTIR) and Pyrolysis-gas chromatography-mass spectrometry (Py–GC–MS). The right parameters and conditions to be used during the cleaning process were, therefore, determined. The chemical selectivity of the cleaning process allowed us to complete the treatment safely while preserving the restoration.

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Tackling conservation challenges using erbium lasers: case studies at the British Museum

Cited by 4 publications

References 0 publications

Er:YAG Laser Cleaning of Painted Surfaces: Functional Considerations to Improve Efficacy and Reduce Side Effects

Er:YAG Laser Cleaning of Painted Surfaces: Functional Considerations to Improve Efficacy and Reduce Side Effects

Successes and challenges in laser cleaning metal artefacts: A review

Investigating the Potential of the Er:YAG Laser for the Removal of Cemented Dust from Limestone and Painted Plaster

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