A keszthelyi Szent Miklós-kápolna külső és belső középkori falképegyüttesének feltárása és restaurálása

Absztrakt

Exploration and conservation of the external and internal medieval mural paintings of the St. Nicholas chapel in Keszthely

The exterior and interior walls of the medieval church in the Szent Miklós (St. Nicholas) cemetery in Keszthely were once covered by lavish Gothic frescoes. After the Ottoman occupation, the church stood abandoned and was in ruins for a long time before having been rebuilt in Baroque style in 1717 and renewed in 1775. In 1909, the chapel was transformed into a burial place for Archbishop Kolos Vaszary (born in Keszthely): the building received a Neo-Romanesque exterior, and the interior and the Vaszary crypt were covered with decorative and figurative painting. The building was used as a cemetery chapel during the 20th century, but by the turn of the millennium, its condition had deteriorated seriously and it became unusable. During the external architectural reconstruction, Gothic frescoes depicting six standing figures were discovered on the outer walls of the sanctuary; these were conserved/restored in 2004. The correction of the slightly worn retouches and a repeated hydrophobising treatment became necessary for further protection and aesthetic reasons by 2022. After that, the early 20th-century paintings of the interior had been documented for the archives before their removal to expose further parts of the lavish Gothic murals. The two rows of frescoes in the nave depict the life of Christ, while the ones in the sanctuary include some standing figures of saints and a Maiestas Domini image. The revealing of the murals was problematic for more than one reason: we had to remove the cement-based adhesive of the tiles applied to the plinth in 1909 and the calcium oxalate crust that had formed on some deteriorated murals. The formation of this crust may be connected with the presence of lichens in the building, which released oxalic acid, thus promoting the accumulation of an insoluble crust containing calcium oxalate. The crust was likely made harder by a fire that broke out in the church building. A thick layer of plaster admixed with stone dust and two thinner, 18th-century lime plaster strata were removed mechanically from the surface of the medieval paintings. After crust thinning, citric acid solutions were used to make the frescoes visible. The exploration, cleaning, and conservation were successful and, in our hopes, the aesthetic reconstruction of the frescoes can also take place in the near future, following an archaeological excavation
and the dismantling of the gallery that now cuts the Gothic murals in two.