Chemical and Laser Cleaning of Corrosion Encrustations on Historical Stained Glass: A Comparative Study

Abstract

The aim of this research work was to conduct a comparative study on the effectiveness of the application of chemical cleaning versus laser cleaning in the removal of surface congruent dissolution products from a potash-lime–silica historical stained-glass sample. EDTA was selected as the chemical cleaning agent. Laser cleaning was performed using a 238 fs pulse UV (343 nm) laser. The comparative cleaning studies were carried out on a stained-glass piece supplied by the Maison Lorin Glass Restoration Workshop from Chartres, France. Given the complex nature, irregular thickness and heterogeneity of the encrustations found on the glass, the two cleaning approaches were carefully performed step by step, while monitoring the process using an optical microscope. Raman spectroscopy and field emission scanning electron microscopy were used to characterize the changes induced on the sample surface during the cleaning process. The results demonstrate that the two cleaning approaches were able to eliminate the outer surface dark layer associated with carbon compounds, as well as the external part of the white layer generated by the crystallization of salts, formed with the dissolved elements after a reaction with the air. A comparison of the advantages and disadvantages of each method is also presented.

Analytical Evaluation of Laser Cleaning Effectiveness in the Context of Contemporary Muralism

“…Among these advancements, the widespread adoption of laser cleaning technology has emerged as a transformative force, successfully applied to a remarkable array of historical treasures. Over the past two decades, laser cleaning has been widely employed to preserve diverse materials including stones, paintings, and archaeological finds such as metals, textiles, wood, glass, bones, and more [1][2][3][4][5][6][7]. Unlike conventional cleaning methods that often involve the use of solvents, which might be harmful to the environment and operators, laser ablation technology offers a sustainable alternative that overcomes the limitations of chemical processes.…”

Evaluation of Cleaning Soiled Deposits and Crusts from Archaeological Glass Using Laser Treatment with Ag/Au Nanoparticles

“…However, it is insufficient when heavy hard crusts on glass surfaces are exposed to corrosion and extracted from excavations [12]. Furthermore, chemical cleaning based on the use of chemicals, such as solvents, acids, and various alkalis, is not desirable in the case of corroded glass artifacts, as they are fragile and full of pores, which can penetrate those pores and change the properties, weaken, and increase damage to the material [13,14].…”