The LACMA Conservation Center has been continuing its research activities within the GREENART project, aimed at the development and validation of greener and more sustainable materials for the conservation of cultural heritage, focusing on two objects: one of the soffits from the Damascus Room (1766–67) and Tibetan Altar Table with Auspicious Symbols (19th century). These objects present different, yet equally complex, challenges that cannot readily be solved with traditional conservation methods.
In this context, the materials developed under the GREENART project have proven helpful for the removal of various types of coatings, soiling layers, and soot from different painted surfaces on which they are being tested by the project’s partners. What distinguishes these materials is their reduced toxicity, their selectivity, and the more gradual action of the cleaning systems, aimed at ensuring the preservation of even the most sensitive materials by acting at the interface of the substrate to be removed.
Among the materials tested, we have a wide range of greener nanofluids, along with hydrogels and organogels. These gels are three-dimensional networks that hold large amounts of liquid—water-based in hydrogels and organic solvents in organogels. They slowly release the cleaning agents, helping to limit how deeply they soak into the object and how much evaporates into the air. As a result, they significantly reduce risks to both the environment and human health.
In the case of the Tibetan altar table, the main risk of using traditional solvents like ketones or aromatic hydrocarbons is that they may potentially undercut layers we wish to preserve, such as the varnish, and soften the paint layers. When used as standalone solvents delivered with cotton swabs, rather than in a gel system or as nanostructured fluids, larger quantities are released onto the object's surface and into the environment, increasing the risk of damaging underlying layers. In contrast, nanostructure fluids and gel systems allow for more controlled application and reduce solvent spread, making them a safer and more effective alternative. Among the developing partners, the Center for Colloid and Surface Science (CSGI) and The State University of Campinas UNICAMP provide a diverse range of materials that allows LACMA’s Conservation team to select cleaning systems that target specific materials, ensuring the process is as minimally invasive as possible.
As for the soffit panel from the Damascus Room, other cleaning materials more recently adopted by the conservation field such as polysaccharide-base gels or oil-in-water emulsions may not be sufficiently retentive, potentially introducing large amounts of water into the porous and sensitive painted surface and substrate. Tests conducted with the hydrogels provided by CSGI showed that, unlike traditional systems, these new materials allow for a gradual release of the fluid while providing excellent adaptability to the surface.
The study of both objects is still ongoing, and includes further laboratory testing at LACMA’s Conservation Center to identify the most suitable cleaning systems or combination of systems for each object and to optimize the application methods. However, we can already see that the new systems developed within the GREENART project show great potential for challenging case studies, offering numerous low-impact alternatives while promoting environmental sustainability and safeguarding both sensitive objects and the health of conservation professionals.