Kouvola team tests ethanol to save prehistoric rock paintings

Conservators are testing high-strength ethanol to remove lichen from prehistoric rock paintings in Kouvola, in what Yle reports is the first such cleaning trial in Finland. The aim is to prevent the paintings at Jyrkkävuori, on the shore of Lake Rapojärvi, from being lost.

The rock face is badly weathered, and crustose lichen has grown into the stone. Project leader Arja Parkkonen, an art historian with the Finnish Ancient Art Society, says 96 per cent ethanol can kill the lichen. The team is also testing a 74 per cent solution to compare their effectiveness.

The paintings, made with red ochre, stretch across about 10 metres of rock and depict people and elk. Another image may show a boat. The site’s distinctive motif is a human hand with fingers spread apart; no similar image is known elsewhere in Finland. The paintings were discovered in 1984.

When the project began last spring, almost all the images were covered in lichen. Early results are encouraging, Parkkonen says, but the lichen has not been completely removed and further treatments are needed. Work and photographic documentation are expected to continue until 2029.

Ethanol has previously been used in Finland to clean rock carvings made by hammering or engraving, but not painted images. Past attempts to clean paintings by brushing or rinsing them with lake water were later abandoned. The current five-year project has permission from the Finnish Heritage Agency.

Archaeologist Oskari Sairanen of the Kymenlaakso Museum, who oversees the work, says lichen growth is a widespread threat to Finland’s roughly 140 rock-painting sites. If the paintings disappear, he says, they cannot be brought back.