Painting of artist’s rural retreat, unseen in exhibition since 1895, will now go on show at National Gallery

Tracking down lost works of art usually involves poring over obscure documents in galleries, archives and libraries, searching for clues. But the curator of a forthcoming National Gallery exhibition on Claude Monet will be featuring a “missing” painting that he found through a startlingly straightforward route – a Google search.

Thomson, who is Watson Gordon professor of fine art at Edinburgh University, told the Observer: “It’s a picture that’s been off the beaten track, off the radar, and we’re going to have it in the show. Its whereabouts weren’t known… It’s exciting.”

Effet de Brouillard is an atmospheric scene that depicts Argenteuil, near Paris, the rural retreat where Monet lived between 1871 and 1878. It was here that he produced some of his most sublime masterpieces. Thomson thought that the 1872 painting, a hazy view of houses shrouded in fog, would be perfect for his exhibition, Monet & Architecture. He had already secured loans from private and public collections, and this seemed like a missing piece in the jigsaw.