At the National Museum & Gallery, Cathays Park, Cardiff, until 10 August
The second son of a large, landowning Welsh family, Thomas Jones was apprenticed to his country's greatest artist, Richard Wilson, before heading for the 'magic land'of Italy. The landscapes he painted there were competent but, like his sketchbooks, lacked a personal vision: not surprisingly, he failed to secure patronage. Jones, it appeared, was destined for obscurity, writes Richard Weston.
And then something magical happened. In 1781, in Naples, despairing of selling his work, he began to make tiny oil sketches from the roof of his studio.
Devoid of narrative, they depicted the weathered, decaying walls of ordinary buildings with a directness and intensity unlike anything in previous art.
Research has shown that the compositions were more calculated than they appear and were probably not completed outdoors, but this does nothing to diminish their precocious originality.
Following the premature death of his elder brother, Jones inherited the family estate and returned to Wales to live the life of a gentlemen. He produced moving sketches of the surrounding countryside but never rivalled those made in Naples, which only came to light in 1954. Honed by photography, plein air studies and the worked surfaces of Modern art, aesthetic sensibilities were finally alert to his achievement - hence this fascinating exhibition and its beautiful catalogue.
By comparison with a A Wall in Naples or Buildings in Naples (pictured), Vermeer's View of Delft appears almost rhetorical, and only with Modernism do we encounter a similar directness and apparent detachment in depicting reality. The results strike many as melancholic - meditations on a city that history was passing by. Or could it be that Jones, like Adrian Stokes a century and a half later, drew sustenance from these simple Mediterranean buildings, finding in their weathered surfaces and perfectly proportioned apertures an emotional depth that now eludes all but the greatest architecture?
Richard Weston is a professor at the Welsh School of Architecture