producer alexander korda tooled "21 days" to be a star vehicle for vivien leigh, but his constant interference caused great problems on the set. he rearranged shooting schedules and even added a sequence; director basil dean reputedly never saw a rough cut or the finished product. the title change to "21 days" was attributed to korda. principal photography took place in 1937 at denham film studios, with the production shot in black and white. vincent korda, alexander's younger brother, was the art director on "21 days" and responsible for the sets.