the entire feature in sound, but in reality the silent version - which was largely completed - was cleverly used for several sequences with non-synchronous sound and dialogue where the actors faces were not visible. The opening 6 minutes of the sound version are silent, with musical accompaniment, as are numerous shorter scenes later, and the entire final chase sequence is from the silent version with occasional non-synchronized vocal interjections, including Donald Calthrop's last words on the dome of the British Museum's reading room. Thus it can be argued that the sound version of Blackmail, despite BIP's publicity, is a "part-talkie". Gaumont-British's High Treason, directed by Maurice Elvey was also turned into a sound film mid-way during production. Much like Blackmail, much of the silent footage in High Treason was maintained and dubbed over for the sound version, with Elvey himself voicing some of the minor characters. Blackmail, marketed as one of Britain's earliest "all-talkie" feature films, was recorded in the RCA Photophone sound-on-film process. (The first U.S. all-talking film, Lights of New York, was released in July 1928 by Warner Brothers in their Vitaphone sound-on-disc process.) The film was shot at British and Dominions Imperial Studios soundstage in Borehamwood, the first purpose-built sound studio in Europe. Lead actress Anny Ondra was raised in Prague and had a pronounced Czech accent that was felt unsuitable for the film. Sound was in its infancy at the time and it was not possible to post-dub her voice. Rather than replace her and reshoot her scenes, actress Joan Barry was hired to speak the dialogue off-camera while Ondra lip-synched her lines. This makes Ondra's performance seem slightly awkward. Hitchcock used several elements that would become Hitchcock "trademarks" including a beautiful blonde in peril and a famous landmark in the finale. Without informing the producers, Hitchcock used the Schüfftan process to film the scenes in the Reading Room of the British Museum since the light levels were too low for normal filming. The film was a critical and commercial hit. The sound was praised as inventive. A completed silent version of Blackmail was released in 1929 shortly after the talkie version hit theaters. The silent version of Blackmail actually ran longer in theaters and proved more popular, largely because most theaters in Britain were not yet equipped for sound. Despite the popularity of the silent version, history best remembers the landmark talkie version of