AIC's 41st Annual Meeting

The St. Nicholas First Croatian Catholic Church, located in Millvale, Pennsylvania, a borough neighboring Pittsburgh, contains expansive murals painted by the Croatian immigrant artist Maximilian Vanka in the 1930s and 1940s. Pictorial content in the 22 murals covers 11,000 square feet of interior space and depicts scenes of industry, religion, social injustice, and the horrors of war. In the 75 years since their completion, the murals have been subjected to a variety of damage. A hurricane in 2004 struck the building, resulting in water infiltration in the walls and the development of local areas of efflorescent bloom on the murals. Further, pollutants from industry and auto emissions have resulted in darkening colors of the surface of the murals. This case study addresses shortcomings of previous treatment materials, treatment of efflorescence using inorganic materials designed for murals, and removal of dirt from the water-sensitive surface by using new materials designed for the conservation of modern paints. Samples collected from untreated efflorescence were examined by scanning electron microscopy – energy dispersive spectroscopy (SEM/EDS), identifying a strong presence of sulfur in the salts. The presence of sulfur supported the application of the inorganic method, known in Italy as the “barium method” or the “Ferroni−Dini Method”, to chemically de-sulfate the efflorescence and re-form calcium hydroxide by the use of poultices. Test areas were examined using SEM/EDS before and after poultice application to confirm the reformation of calcium in the wall. Once the efficacy of this method was supported, nanoparticles of both barium and calcium were used for improved results. SEM/EDS of samples collected from areas treated by nanoparticles confirmed that sulfates were removed from the surface and stabilization of the wall was successful. Cleaning the water-sensitive medium was handled using recently developed cleaning systems. Aqueous mixtures were adjusted to a lower pH and water/oil emulsion gels were designed to prevent water from penetrating the sensitive surface while lifting surface dirt.