In Dark Passage, Humphrey Bogart plays Vincent Parry, a man wrongly convicted of his wife’s murder. At the start of the movie, he escapes from prison, and halfway through he gets plastic surgery to enable him to search for his wife’s killer without detection.
This gave the studio the problem of what to do about Humphrey Bogart in the early part of the film. After all, if Parry was going to look like Bogart after the surgery, he couldn’t very well look like him beforehand.
Rather than have another actor play Parry until the surgery, the filmmakers decided to use first-person camera, meaning that we see the world through Parry’s eyes, with the other characters addressing the camera directly, as Lauren Bacall does in the shot below.
As a result, Humphrey Bogart doesn’t appear on screen for almost 36 minutes, and even then his face is covered. The bandages don’t come off for almost an hour, meaning that Bogart’s face is visible for only the last forty minutes of the film.
Perhaps unsurprisingly, when Jack Warner at Warner Bros. saw the rushes, he baulked at the idea of paying for a star like Bogart and then using only his voice for the first half of the movie, but by then it was too late.