Blackmail (1929)

Hitchcock was keen to use sound in a creative way, and one scene from the film has become particularly celebrated. Alice has stabbed to death a man who tried to rape her. At home the next morning, Anny's parents tell her about the murder. As she sits down to have breakfast, the family are joined by a local gossip, who talks endlessly about the murder. When her father asks her to cut a slice of bread, Alice becomes increasingly agitated, until finally she drops the knife.

The most striking difference between the two versions is the way in which Hitchcock distorts the dialogue to evoke Alice's tumultuous mental state, so that ultimately only the word 'knife' is distinct. The word becomes more and more pronounced until finally it reaches a climax with Alice dropping the bread knife. It's certainly a very powerful effect. But if you watch the sound version scene with the volume turned down, followed by the silent version, you'll see that in other ways, the silent version is more interesting. Notice the way we see the shadow of Alice's hand crawl across the bread before she picks up the knife. The result is that the silent version has a very different feel - less startling, perhaps, but more creepy and unsettling.

There are other significant differences between the two scenes. For one thing, the part of the gossip is played by two different actresses. Secondly, the silent version features more shots, which elsewhere in the film has the effect of 'speeding up' the action, even if the scene actually takes up more screen time. Whether that is the effect here is open to question.