Safe cleaning strategies for the gilded surfaces of the Ghent Altarpiece
On 30-31 October 2025, the Art Salinity and Acidity Project (ASAP), the Materials Science for Conservation Research (MatCoRe) unit – jointly supported by KIK-IRPA and the Université libre de Bruxelles (ULB) – and the Ghent Altarpiece conservation-restoration team came together for a unique two-day collaboration focused on the gilded areas of the paintings.
This encounter brought together Dr. Elena Aguado (ASAP, Escuela Superior de Conservación y Restauración de Bienes Culturales (ESCRBC) in Madrid) and Chiara Bianchi (ASAP, FeliX Art & Eco Museum), working alongside Dr. Hélène Dubois’ Ghent Altarpiece conservation-restoration project team, as well as Dr. Francisco Mederos-Henry and Amandine Colignon from the MatCoRe unit, combining complementary expertise in heritage science, water–pictorial layer interactions, and conservation practice.
Together, the teams explored how detailed pH and conductivity mapping can guide the safe design of water-based cleaning systems for the gilded surfaces of the Ghent Altarpiece. Because the metal-carboxylate alteration processes affecting these areas can be influenced by water, understanding and controlling its physico-chemical properties becomes essential. Not to refrain from using water, but to avoid triggering or accelerating degradation pathways characteristic of oil-gilded surfaces.
This knowledge exchange addressed a major conservation challenge: aqueous methods remain the most effective way to clean these gilded surfaces, but their use requires a refined understanding of the materials' chemistry and their interaction with water. This helps minimise long-term risks associated with water-induced reactions such as the formation or crystallisation of metal carboxylates.
Thanks to the generous support of the Fondation Périer-D’Ieteren, the Art Salinity and Acidity Project (ASAP) team travelled to Brussels and Ghent to share their specialised expertise and collaborate on developing tailored aqueous cleaning formulations adapted to the specific needs of the retable.
These two days represented an exceptional and valuable intersection of conservation-restoration, materials science, and heritage science, uniting interdisciplinary insight to co-develop safer and more sustainable cleaning strategies for one of the world’s most iconic masterpieces.
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Additional funding for the third phase of the conservation of the Ghent Altarpiece
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