On one of the computer monitors in Bowman's pod (visible in
the widescreen version only), scratches and a rather obvious film-edit splice can be seen, giving away the fact that the computer graphics are rear-projected film clips. The same scratched-up section of animation is seen in two or three subsequent shots of the pod's control panel.
Bowman inhales deeply before attempting to re-enter the ship from the pod. Arthur C. Clarke in an interview later noted that this is incorrect. Bowman should have exhaled, as the vacuum of space would have damaged his lungs had they been full of air.
HAL's verbal description of his chess move (Q-B3), given what he shows on the screen, are from Frank's point of view. This is often regarded as an error, since in descriptive chess notation, the rank is described from the point of view of the player making the move. It should be Q-B6. HAL's errors can be considered either script goofs or clues revealing his internal conflict, since he is supposed to be infallible.
HAL knows that Dave and Frank were planning to disconnect him because, "... although you took very thorough precautions in the pod against my hearing you, I could see your lips move..." but moments before discussing the plan, when Dave and Frank were directing HAL to rotate the pod, their lips clearly visible to HAL, HAL did not comply with their request.
As Dave Bowman climbs into HAL's logic center to shut him off, the seal on his suit's left hand is broken and the glove separates from the suit (due to the swing). The glove is reattached once he enters the logic center.
The scene where Dr. Floyd talks with Russian scientists in the space station is shot from two angles. One of the seated women has her legs crossed in all the shots from one angle and uncrossed in all the shots from the other angle.
The bone Moon-Watcher uses to beat the enemy ape is a femur (upper leg bone), as indicated by the sideways projecting "arm" with a ball at the end. However, the bone shown rotating in the air is a tibia (main bone of the lower leg), as indicated by its blunt ends.
In the Pan Am lunar shuttle, we see the Clavius Moon Base approach through the viewing window of the pilot's cockpit in a view like an airplane approach. In the next shot, we see the exterior of the craft, and the cockpit is shown pointing straight up towards the black sky as it lands on the landing gear beneath the craft. It would be impossible for the pilots to view the Clavius approach from the cockpit if landing with reverse thrust engines. All they would see is the sky straight above, and it would be relatively still from their point of view.
When the astronaut leaves the pod to replace the AE-35 unit, he is holding it in his right hand so he can use his left hand to control his thruster backpack. In the next shot showing him maneuvering toward Discovery, the AE-35 is in his left hand.
After Dave Bowman takes his food out of the food slot, two of the containers in his tray exchange positions by themselves. When he first removes the tray, there is a dark red container all the way to the left and a grayish one next to it. When Dave makes his way to the table to eat, the red one and the gray one have switched places.
As Heywood Floyd approaches the Tycho Monolith in the shuttle, the Earth is on the moon's horizon. But a short time later, when Floyd stands at the monolith and it emits its signal, the Earth is directly overhead.
When the spaceship is docking at the station, the ship and the station are rotating at the same speed as can be seen in the scenes from the ship's point of view. But in the exterior, zoomed out shot of both of them, they are clearly rotating at radically-different speeds.
When HAL manipulates Frank's space pod to attack him, the pod is shown rotating to face Frank, then fully extending its arms as it accelerates. When the pod is shown rolling away into space after hitting him moments later, its arms are retracted again.
When Bowman is disconnecting HAL in the logic center, he turns a key and a corresponding clear plastic block slides out. However, when he skips the #1 block in one series and turns the key for the high number in the next series, the #1 block in the previous series slides out.
As the shuttle is making its final approach we see a shot of the shuttle's cockpit with the station out the window. The schematic of the docking port on the interment panel does not match the rotation of the station.
During the BBC interview the interviewer notes that the delays due to the distance of the Discovery from the Earth have been edited out. However, during the interview the astronauts do not move much, something that would be unlikely if they had to wait seven minutes between each question and answer.
During Dr. Floyd's chat with the Soviet scientists aboard the space station, two of the women's coats, draped over the backs of their chairs, disappear, reappear then disappear again (in one case, the coat appears to have fallen behind the chair).
At 25 minutes into the movie,in the cockpit of the shuttle conveying Dr Floyd to the space station, between the 2 pilots there are 3 screens and one can clearly see IBM above the middle screen. In subsequent shots as they prepare to dock, On those same 3 screens, IBM mysteriously vanishes.
While Frank is on the tanning bed listening to his parents' birthday greetings there is a cut showing Dave asleep in his 'sleeping pod' that shows the tanning bed at Dave's head, empty. Likewise, Dave is not shown inside the pod while Frank is shown on the tanning bed. The lighting in each cut also changes.
When Dr. Floyd has finished flipping through photographs on his way to the TMA-1 moon base, during the cut where he says "Deliberately buried," he is holding a different photograph from the one he is holding in the preceding and succeeding shots.
When Dave is approaching the emergency airlock, we can see through the pod window that the door is labeled Manual Operation Only, and the unlocking mechanism to the right of the door is labeled Manual Lift. In the next shot, an exterior of the pod closing in on the airlock, the unlocking mechanism on the right is now labeled Manual Operation Only instead of Manual Lift.
The rotating room scene on the Aries Moon Shuttle -- the actress rode the elevator up form the passenger deck below. She walked along a curving floor until she was upside down to her previous position, then she walked into the left hallway.
In the published ship designs the Aries flight deck was perpendicular to the passenger deck. The set rotated too far and the actress walked into the wrong passageway. The set should have rotated only 90 degrees and she should have walked up through the the walkway on the ceiling.
The Earth hangs in the sky near the horizon at Tycho in long shots of the monolith pit, but Tycho is at 43 degrees south latitude on the Moon, so Earth would appear in the sky halfway between the horizon and zenith.
The quadrupeds shown coexisting peacefully with the apes in the early scenes are tapirs, Tapirus bairdii. They live in tropical forests in Central America and northwest South America. You'd never see them in Africa (outside of a zoo), nor in the very dry habitat shown in the film. But tapirs that are accustomed to humans can be quite docile (though obstinate), and they look exotic to most viewers, so they were a reasonable choice for the film.
When the lunar shuttle is landing on the moon, the Earth is seen in the background four times. The first time the Earth is lit from the right. The second time, when you see the men in suits on the lunar surface looking up as the shuttle comes in to land, the Earth is lit from the left. The next two times the Earth is seen, it is back to being lit from the right. Since the moon revolves around the moon once every 28 days, the phase of the Earth should not change this quickly.
When the astronauts on the moon are shown walking toward the unearthed sentinel, they are walking normally, as if on earth. The moon's gravity is one-sixth that of earth; hence, they should have appeared to "bounce" a bit when walking, as was seen in the later Apollo moon landings.
In the first part of the film, when one of the small pod spaceships is landing on the moon, we see dust billowing up from the landing pad. Billowing is caused by the collision of dust and air molecules. But since there is no air on the moon, the dust would not have billowed, and should have been sprayed outward in all directions.
On each of the monolith's first two appearances, the upward camera shot shows the sun/moon or sun/earth in line, artistically above the structure. In both cases, however, it's early morning on earth or the moon, and the sun should actually be on the horizon.
During the ape sequences in the beginning. The skeleton shown is of a modern human. The apelike proto humans with face/heads like that would be quite stocky in build. The skeleton is clearly of a modern humanoid.
When David Bowman re-enters Discovery he uses the right "hand" of the pod to rotate the manual lift control for the pod bay door. While it it possible for this to work with the pod's thrusters compensating for the rotational torque, it would be more efficient if there were a left "handhold" to keep the pod from rotating around the control, instead of spinning the pod around.
When Dave, then Frank, go outside the Discovery to replace the AE-35 unit, neither one communicates with the other man who remains inside the ship to monitor the operation. In reality, there would be almost constant talk between the two because of the inherent dangers in going EVA.
As Dave is disconnecting H.A.L., H.A.L.'s voice gradually slows down and stops similar to a tape recording or phonograph record slowing down. H.A.L. , being a digital computer, would not have failed in that manner but with static noises and increasing losses of signal.
When Bowman reenters the ship, he is exposed to vacuum for no more than 10 seconds before operating the repressurization valve. Scientific evidence shows that this would indeed be survivable without grievous harm, notwithstanding the sensational depictions in other movies.
When Heywood Floyd is talking to his daughter on the picture-phone, she moves slightly out of frame but remains in the shot. Modern cameras can move around to "follow" a person, Stanley Kubrick and Arthur C. Clarke foresaw this.
Stanley Kubrick considered shooting the Dawn of man sequence on location in Southern Africa but was unable to due to the expense and also the likelihood of shooting being disrupted by adverse weather. Rear projection as well as colour separation overlay (blue-screen) were considered but not used because both methods would lack visual quality. Instead with assistance from MGM's special effects department the crew developed a new front projection system that used 8x10-inch slides taken on location in Africa. A high-intensity projector was aligned at a perfect angle from the camera and used to project the slide through a partially-transparent mirror that simulated placing the camera and projector in exactly the same place - thus the shadows cast by actors and set objects on the screen were invisible. However the screen material was only available in rolls of limited width and there were variations in reflectivity between rolls. Tearing the material up into small sections and "collaging" them together provided the best uniformity but with effort some variation can be seen in places.
The famous centrifuge area of Discovery provides simulated gravity for the crew. However, the pod bay does not rotate, and is gravity-less. Poole and Bowman appear to walk normally there because they are wearing the same "grip shoes" as in other scenes in gravity-less parts of the ship.
When the hatch is blown with the "explosive bolts", it appears to vanish when it should have been in between Dave and the Discovery, blocking his entrance, However, the door isn't actually detached in this sequence but is, rather, forcibly opened with the door sliding into the side of pod as it normally would, just much quicker due to the explosive bolts being fired.
When Bowman is carrying out the EVA to replace the AE-35 unit, Discovery's aerial is seen rotating. Normally the aerial is directed to Earth, and unless the ship itself was changing position the aerial would appear stationary. However, the device which controls the positioning mechanisms of the aerial is the AE-35 unit-the unit being replaced. During the time Bowman is exchanging the AE-35s the aerial would have no hardware control, and there is also a small but real possibility that the replacement AE-35 might be faulty. It is reasonable to assume that the aerial would first be rotated to its default position (facing forward, away from Earth) and mechanically locked down until the new AE-35 unit is installed and checked out. The rotation visible in the scene is consistent with that.
When HAL kills the three hibernating astronauts a display stating "COMPUTER MALFUNCTION" appears. Given the absolute confidence in the computer it seems odd that the provision of such a display would be necessary on the ship.
When the moon monolith, which has been buried for millions of years, is struck by sunlight, it transmits its message to Jupiter, notifying its creators that humans must have evolved to point of space travel. But given that unfiltered sunlight on the moon is extremely destructive, even without knowing about the impending transmission the humans probably would have built a structure around the excavation site to protect whatever they found from direct sunlight.
To come up with a convincing effect for the floating pen in the shuttle sequence, Kubrick decided to simply use a pen that was taped to a sheet of glass suspended in front of the camera (in fact, the shuttle attendant can be seen to "pull" the pen off the glass when she takes hold of it). If you watch carefully around the upper left corner of the screen just before she catches the pen, you can see the glass briefly reflecting light as it rotates to give the floating effect to the pen. (On the BluRay release, the sheet is clearly visible through most of the scene. Even swirl marks and what looks like a palm-print can be seen.)
On the space station, right after Dr. Floyd clears security, and before he meets the Russians, he and another man are strolling along the curved floor of the station. Their bodies' orientation should be radial to the curvature of the floor, appearing to lean forward in the frame, but instead they are perpendicular to the orientation of the frame: they are walking downhill rather that walking along the bottom of the curved floor.
Although the meeting on the moon is presented indoors, in a shirt-sleeve environment, it is still on the moon. Dr. Floyd walks around the room in full Earth gravity, rather than using the low-gravity "skip" that was adopted by the Apollo astronauts.
While Poole and Bowman are watching the BBC 12 interview, the
right flat screen is slightly ahead (about two frames). This is due to both screens being rear-projected film clips from two projectors. An actual video feed would be completely synchronized.
When Dave goes out to repair the AE-35 unit the first time, he parks the pod away from Discovery and rotates it so that the door faces the spacecraft. During the rotation, the lights of the pod reflect on the left side of the screen.
As the PanAm shuttle closes in on the space station, the shuttle and station rotate synchronously, so you see the station stay still through the shuttle's windows. However the computer schematic displayed in the cockpit keeps rotating.
At the end of the film, Dave uses the last remaining pod to get a closer look at the huge monolith. The hangar bay door that opens is the one in the center. The center bay was from the pod that killed Frank and was drifted into space. The bay door to the left (outside perspective, looking at the Discovery) was from the pod Dave used to retrieve Frank's body. The pod became useless upon explosive re-entry of Dave in the Discovery, so the only left pod should be the one at the right bay door and not the center door.
While Dave gets outside the Discovery in attempt to retrieve Frank's body, HAL kills the hibernating crew, a shoot of the hangar bay shows the door to the left open. When Dave is back in the Discovery and away to shut down HAL, the same door is closed.