Marion is stabbed repeatedly in the torso while in the shower then presses her front against the wall before turning around and sliding down. But there is absolutely no blood left behind on the shower wall.
As Marion falls out of the shower, her hair is soaking wet. But in the famous still shot of her lying on the floor, her hair is relatively dry.
Janet Leigh's body double is obvious when Norman is pulling Marion from the tub onto the shower curtain; the dead woman has painted toenails while Janet had clear nails during the stabbing shots.
At the car dealership, the same extras (people on the sidewalks) are seen repeatedly, walking in different directions
When "Mother" exits her room and charges Arbogast, she slashes downward towards his chest. But the wound is on his face when he falls backward down the stairs.
Detective Arbogast phones Sam's store to tell Sam and Lila what he's found out and suspects, but they're not the ones who hired him to find Marion - Marion's boss hired him.
Fairville on the 19th and 20th of December shows no signs of Christmas.
In the closeup of Marion's face when she's dead on the bathroom floor, her eye is wide open and her forehead is wrinkled from that expression. Once dead, her eyes and forehead muscles would have relaxed so her forehead wouldn't have been wrinkled.
At the time of the film's production in 1959, the California Highway Patrol did not use Fords in their fleet (only Dodges with the famous D500 power plant). Also the livery of the vehicle is incorrect; only the front doors were painted white. The roof and rear doors were black. However,the CHP star on the front doors, as well as the emergency flasher and spotlight arrangement ARE correct and the uniform worn by Mort Mills is as well.
When Marion is in the motel room writing in the notebook with her bankbook above it, the balance is added incorrectly after the Jan. 15 deposit of 48.38. The previous balance was 752.74, so the new balance would be 801.12, but it was 800.12 in the bankbook.
The title card fixes the date as December 11, but when Marion is deducting the cost of the car from the $40,000 later that same night, the last date in her bank book is shown as being January 20. People often "backdate" checks.
After Marion steals the money it takes her almost a day and a half to get to the Bates Motel. However when Arbogast telephones her from near the motel after interviewing Norman, he suggests he is only about an hour away. Similarly when Lila wants to visit the motel she says it will take a hour or less. This is because Marion drove from Phoenix to the Bates Motel, making sense that it took Marion that long to get there. On the other hand, Lila is at Sam's hardware store in Fairvale, which is about an hour from the Bates Motel and the phone booth Arbogast was calling from.
When Lila approaches Mother in the fruit cellar, Mrs. Bates is seated in a four-legged chair. After Lila touches the corpse, it slowly spins around as if it's sitting on a swiveling chair. The effect was achieved by a prop man lying on his back rotating a camera head with wheels underneath Mother.
When Janet Leigh is in the car dealer bathroom getting the cash, as the envelope is being returned to her purse the top couple bills fold back revealing a $1 bill, not another $100 as the stack is expected to contain.
In the shower, when Marion is seen in front of the shower curtain, there are two different water jets, visible by different angles towards each other, revealing that besides the shower head, an additional source of water was used.
When Norman drags Marion from the bathroom to wrap her in the shower curtain, she is wearing panties.
When Marion Crane leaves town and it becomes dark outside, the rear shot of the car driving into a cloudy night shows very noticeable white scratches in the sky. Apparently, a scratched image of the dark cloudy sky was placed above the footage of the car driving to make it appear as though the car was driving in the night.
When Norman first meets Marion his first words to her were an apology for not hearing her on account of the rain. He then asks her to accompany him into the office. His lips don't even move during this scene and he gestures with a hand signal for her to go inside instead; the audio must have been added later in post-production.
Indeed, if you look carefully it is apparent that it's Marion who is talking to Norman and that all the dialog in this scene was replaced.
Indeed, if you look carefully it is apparent that it's Marion who is talking to Norman and that all the dialog in this scene was replaced.
When Marion drives away from the police officer, the unmistakable sound of a 1957 Ford starter can be heard, but she doesn't reach for the key (which is left of the steering wheel on the dashboard), or make any visible movement to use the shift lever.
When Marion first gets out of her car and meets the salesman at the used car dealership, a crewmember is reflected in the car door. Part way through the shot, he suddenly crouches down.
Marion is in her apartment changing her clothes after stealing the money; as the camera dollies toward the money lying on the bed, a shadow of the camera or member of the crew briefly appears on the bedspread in the lower-right portion of the frame.
When Lila and Sam are walking from their motel room to the office, the reflection of a crew member can be seen in the window between rooms 1 and 2.
When Marion pulls into the motel during the rain and sees the office, she drives over to it and stops. In the next shot two lights on a stand can be seen to the immediate left of the office, left by the crew.
The shadow of the camera falls on the lady examining the pesticide can in Sam's hardware store.
When Norman suggests Arbogast to join him while he changes sheets, Arbogast notices Norman pause and then move past the first cabin, after which he spots a sitting figure of a lady in the window of the house, whose shadow actually appears to be standing without support.
The drive from Phoenix to Los Angeles (the presumed location of the film's fictional suburb Fairvale, California) takes roughly 5 hours 30 minutes from downtown to downtown in the 21st century. Assuming that Fairvale is closer and traffic relatively light as it would be in 1960, Marion Crane, the protagonist, would have arrived there well before dark, if not just at dusk.
Even given the time that was "lost" after being stopped by the highway patrolman, the poor weather and the fact she used a secondary highway instead of the larger US 60 (the highway link between LA and Phoenix prior to the completion of Interstate 10) Marion Crane should have arrived at her destination within 4.5-6 hours. There was no reason for her to stop at the Bates Motel.
Even given the time that was "lost" after being stopped by the highway patrolman, the poor weather and the fact she used a secondary highway instead of the larger US 60 (the highway link between LA and Phoenix prior to the completion of Interstate 10) Marion Crane should have arrived at her destination within 4.5-6 hours. There was no reason for her to stop at the Bates Motel.
Fairview apparently isn't that large a community, it seems that Norman Bates would know who Sam Loomis is and wouldn't simply accept that he was showing up at the motel with a wife and have no clue who he was.
The calendar belonging to the Chief of Police reads '17' on December 20th.
On two occasions both Sam Loomis and Tom Cassidy make reference to the actual day's temperature. Tom calls it "hot as fresh milk" while Sam stated it was "Friday anyway and hot". The movie begins on December 11th. Average temperature for Phoenix in the month of December is 68 degrees. [Note: it's possible for a December day in Phoenix to reach into the upper 80s; however, fresh milk from a cow is over 100 degrees.]
It seems a bit too convenient that Marion would have brought in all of her luggage and personal effects into cabin 1, yet she left the key in her car so that Norman could first open up the trunk to put her body in, then drive it out to the swamp.