New York’s Salmagundi Club and a Henry B. Shope Award from the Society of American Etchers, now known as the Society of American Graphic Artists (SAGA). A year later, “Brazilian Builders” took a Charles M. Lea Award at the Philadelphia Print Club Exhibition. Allen also began exhibiting his work in galleries during the 1930s, including at Kennedy and Company and the Grand Central Art Gallery. He later exhibited, became a member and acted as a juror for exhibitions at the Society of American Etchers. In 1934 Allen illustrated the “Sinclair Dinosaur Book” as a keepsake for visitors to the Sinclair Oil Dinosaur exhibit at The Chicago World’s Fair. It contained 7 full-colored illustrations from his paintings. It was followed by the “Sinclair Dinosaur Stamp Album” in 1935. Some 4 million albums were handed out at Sinclair Gas Stations as a promotional item. He took for inspiration the dinosaurs displayed at the “A Century of Progress” World’s Fair, which had opened the previous year in Chicago, and the work of Charles R. Knight. Typical of his dedication, he undertook his own scientific studies under Br. Barnum Brown at the American Museum of Natural History to assure the accuracy of his subjects. In 1938 Allen produced a series of eight lithographs of dinosaurs for Sinclair Refining Company advertisements. But it is for his images of industrial workers from the 1930s that Allen is best known. In scenes of steelworkers such as “The Builders”, “The Connectors”, “Skyriders” and “Up Above the World”, he creates “a vivid and suggestive picture of the powerful rhythm of daily labour and of the fearless readiness of the workers to perform their allotted tasks”. In 1937 he received a commission to create twelve lithographs for the United States Pipe and Foundry Company, showing laborers installing giant pipelines in varied settings. In 1938 the Graphic Arts Division of the Smithsonian's Museum of American History presented a solo exhibition of his work, further elevating his stature as a master printmaker. As one reviewer remarked: “avoiding the present-day epidemic of social protest ... these are graphic depictions of men at work, healthy, satisfied to build for tomorrow, proud in their strength and manual skill”. Allen turned from themes of industry to "more exciting" themes of war in the early 1940s, showing scenes of bombers, convoys, dirigibles, etc. but never strayed from his focus on the role people played. Scenes like "Parachutists",