a printing room. Before the move Gray had worked on paintings of wartime subjects, but here he hoped to find new inspiration elsewhere and overseas, travelling to the Netherlands, Belgium and Spain. He began etching serene, mostly unpeopled landscape scenes. Gray's etchings and drypoints were widely exhibited and reproduced, and sold well both at home and in America. In the decade 1925-1935 he produced about 50 plates, mainly drypoints. The majority of his engravings depicted architectural or landscape views. Printed in signed editions of seventy-five impressions, they entered into many public collections including the Victoria and Albert and the British museums. But as the decade advanced Dundee was hit by depression. His print sales declined, and after the Wall Street Crash of 1929 the American market disappeared completely. Gray moved with his family to London in 1931, and planned to reinvent himself as a portrait painter, since his war commissions had always been praised for the accuracy of their depictions. Art of camouflage Gray's first years in London (1931–33) proved promising. He rented a studio in Chelsea, the same rooms previously occupied by painter John Singer Sargent. There he painted scenes of the River Thames alongside portraiture commissions. In 1933 Lord Brocket requested a full-length portrait, but Brocket died before any payment could be made. This virtually ruined Gray who gave up his studio. Towards the end of the decade Gray became increasingly certain there would be another war. Aware he would be too old to return to the firing line, he began to consider other ways where his experience and skills might be put to use and he became interested in camouflage, specifically how Britain's cities might be protected from the growing threat of German air attack. He visited the Imperial War Museum, using his contacts to gain access to the extensive archive of German, French and English camouflage materials and began a study of large-scale static camouflage. By 1936 he had completed his treatise, Camouflage and Air Defence, which he submitted to the War Office. He was quickly recruited into the Royal Engineers and travelled all around the country visiting sites of national importance, working out ways to hide them. During the early years of World War Two he also devised a kind of steel wool camouflage which was used to conceal large military bases and factories from air attack. Gray's notes from his time as a camouflage