 In the 1940s Black helped to produce the first Gainsborough melodramas an enormously successful series of movies which made stars of James Mason, Stewart Granger and Phyllis Calvert, and increased the popularity of Margaret Lockwood.Black's relationship with Maurice Ostrer was not always easy and he also clashed with the Rank Organisation when they took over Gainsborough.In 1944 Black left Gainsborough to join Alexander Korda.