Painstaking work to uncover a painting which has been hidden in an Edinburgh church for 200 years is under way.
The Ascension of The Lord, painted in 1774 by Alexander Runciman, is considered one of the most significant works of the Scottish Enlightenment.
It is on the ceiling of the St Patrick's RC Church, just off the Royal Mile.
Originally an Episcopalian church, the "idolatrous" painting was covered up when the chapel passed into the ownership of the United Presbyterians.
The Ascension and four subsidiary paintings remained secret as the chapel became a Roman Catholic church 150 years ago.
Now, exploratory work has begun to restore the artwork.
Edinburgh university art historian Duncan MacMillan said Runciman's work was the first significant public religious art since the Reformation.
He said: "If the Ascension can be recovered and the whole scheme restored, it will give us back a work of art that has a central place in the evolution of modern art.
"Reinstating the whole of the original decorative scheme so far as is possible, relighting it and providing interpretation will also celebrate and provide public access to a historic moment in the history of toleration in Scotland and of the nation's churches."