Warner Brothers insisted on shooting the movie in 3-D, although the craze was fading and Sir Alfred Hitchcock was sure the movie would be released flat. Hitchcock wanted the first shot to be that of a close-up of a finger dialing the letter M on a rotary dial telephone, but the 3-D camera would not be able to focus such a close-up correctly. Hitchcock ordered a giant finger made from wood with a proportionally large dial built in order to achieve the effect.
Sir Alfred Hitchcock had chosen a very expensive robe for Grace Kelly to wear when she answered the phone. Kelly balked and said that no woman would put on such a robe just to answer the ringing telephone while she was asleep alone; she would answer it in her nightgown. Hitchcock agreed to do it her way and liked the way the rushes turned out. Hitchcock agreed to allow Kelly to make all costume decisions for her in their subsequent movies together.
Sir Alfred Hitchcock made a special effort to shoot scenes indoors, almost exclusively. Only a few brief shots, usually involving Chief Inspector Hubbard, take place outside. Hitchcock believed the decision to shoot most scenes indoors would create a sense of claustrophobia.
DIRECTOR CAMEO (Sir Alfred Hitchcock): (At around thirteen minutes) Hitchcock can be seen on the left side of the reunion photograph. As he is only seen in a photo, this is the final Hitchcock movie in which he does not appear in person.
Filmed in 3-D, which explains the prevalence of low-angle shots with lamps and other objects between the audience and the cast members. There was only a brief original release in 3-D, followed by a conventional, "flat" release. The New York Times review mentioned it opened with the "flat" release at the Paramount Theater in New York City. The 3-D version was re-issued in 1980.
When Wendice is describing to Swann/Lesgate the middle-aged woman with whom Swann had been affiliated having died from a drug overdose, Wendice was originally to say "middle-aged woman found dead due to an overdose of cocaine". This was in the original script and stage play, but due to the Hollywood Hays Code rules of detailing of drug usage on-screen, the studio officials insisted to Director Sir Alfred Hitchcock to replace the word "cocaine" with the word "something".
Adapted from a Broadway play that opened at the Plymouth Theater in New York City on Wednesday, October 29, 1952, and ran for five hundred fifty-two performances. In the original production, Maurice Evans played Tony Wendice. In this movie, John Williams and Anthony Dawson re-created their stage roles of Chief Inspector Hubbard and Captain Lesgate. J. Pat O'Malley replaced Williams as Hubbard.
Warner Brothers forced Sir Alfred Hitchcock to make the movie to fulfill his contract. Such was his disinterest that he claimed he could have phoned in his direction, and that the action wouldn't have been any less interesting if he'd staged it in a phone booth.
At their first meeting, the untrustworthy Captain Swann is wearing a tie in the colors of a Guards regimental tie. However, this is not a genuine tie, as the diagonal stripes run in the American direction, opposite to British style. This is a contemporary detail used by spivs*. The tie resembles the trustworthy Guards tie well enough to fool most, but gives an excuse if a genuine Guardsman queries one's service record. (*"Spiv" is a Britishism for "a man who lives by his wits without regular employment" (Merriam-Webster's Collegiate Dictionary, eleventh edition).)
In a television interview, Ray Milland said that he had fluffed his lines in a particular scene and ruefully apologized to Hitchcock. Sir Alfred Hitchcock, he said, stared at him stonily for few seconds and then said, "I wound it up, put it on the floor, and it wouldn't go."
The trivia items below may give away important plot points.
After several unsuccessful attempts to film the scene where Margot stabs Swan with the scissors, Sir Alfred Hitchcock said, "This is nicely done, but there wasn't enough gleam to the scissors, and a murder without gleaming scissors is like asparagus without the hollandaise sauce, tasteless."
Sir Alfred Hitchcock lost close to twenty pounds due to nervous anxiety when filming the scissors murder scene. He obsessively rehearsed the scene and shot take after take in order to capture the scene the way he had envisioned it.