Already with the disclaimers: the title of this essay is a convenience which ignores that, while "2001: A Space Odyssey" (1968, Stanley Kubrick, Director) has been, for most of my life, my favorite film, even with the proviso that it cannot be well understood without also reading the novel of the same name (Arthur C. Clarke, also co-author of the screenplay), it has been surpassed in my estimation as both film and science fiction by "Arrival" (2016, Denis Villeneuve, Director), not to be confused with "The Arrival" (1996, David Twohy, Director), which is fun, but doesn't fit in this discussion. Even further, I recognize that the film is even better understood and appreciated if one reads the sadly out-of -print "The Lost Worlds of 2001", a 1972 paperback-only book also by Arthur C. Clarke.
The reasons for now preferring "Arrival" over "2001" are more about what is good about "Arrival" than it is about shortcomings of "2001", nonetheless, it had been a few years since I had really sat down and gave the Kubrick film adequate attention, and I was bothered by a number of things.
I'm going to limit myself to a few problems that I think should have been obvious to, and avoidable by, Kubrick and his collaborators and advisors at the time, not based upon new knowledge obtained since the beginning of pre-production on the film, which is estimated to have begun sometime in 1965.
Importantly, note that Project Mercury was complete, and Project Gemini had already flown the majority of it's missions and returned many color photographs, before 1965. Note that these photographs were all in the public domain and many of them widely distributed at the time, and would have been easily obtained by anyone involved in the production of the film, along with eyewitness accounts from the Astronauts.
I was going to include photos from Gemini and screenshots of the film to illustrate my points, but anyone sufficiently interested can easily obtain these, and can take my word for what I have to say here, or not. Best Google Image Search keywords for relevant Gemini photos are "Project Gemini Photos of Sun" and "Project Gemini Photos of Earth".
Opening title sequence:
I will set aside any nit-picking about relative size of the Moon, Earth and Sun from the fictional point of view in this opening shot, as well as the amount of luminosity of the far side of the Moon when the three bodies are in this configuration. I have no idea, nor do I particularly care, if the stars shown from this point of view, or in any other scene, are correct.
The literally "glaring" problem that takes me right out of the film is the depiction of a yellow sun with a a vastly expansive corona of yellow/orange. The sun, as viewed from space, is intensely white and any "bloom" effect seen in photographs are due to interactions between sunlight and the optics in the camera, and remain white. This scene looks exactly like what it is: a spotlight aimed at a camera in a room full of air, perhaps even with a yellow "gel" in the spotlight.
The Earth and moon look exactly like what they are, static paintings, vastly underwhelming compared to available contemporary photography of Earth from orbit, the Moon from telescopic photos, or the Ranger and other probes, or better paintings based upon the same.
The Dawn of Man:
This is just a potential continuity problem: When the ape-men are examining the monolith, they are in a small depression in the ground which is not very well lit and the sunlight in the projected background photo appears to be coming from a less-than-noontime angle. Suddenly we jump cut to a view looking straight up the monolith and the sun is directly overhead and the moon very nearly so. So, maybe the jump cut also indicated a passage of time to when the alignment of objects in this view was possible. I honestly don't know where in the world, or at what time of year, one can look directly upward and see the sun, but I am sure it happens, so, I should let this one go, or at least defer to someone who knows more than I do about such things.
First Scenes from Earth Orbit:
My main complaint here is just how flat and boring the painting of the Earth is, especially when presented in relatively close temporal proximity to beautiful telescopic photos of the Moon. Look at the Gemini photos of Earth from orbit, how much more colorful they are, and how land-masses are often easily seen, along with the thin envelope of atmosphere along the edge. There is a palpable sense of a spherical object in view, even in two-dimensional photos from very low orbit. Certainly a better painting could have been done than the washed-out mostly-white flat disc we are offered by the film, given, again, the easy availability of Project Gemini color photos at the time of production design.
From late stages of moon lander approach through the end of the TMA-1 sequence:
In addition to a carryover of my complaints about the plain appearance of Earth from space, here I just have another bunch of continuity complaints, that reflect what I can only explain as simple laziness. It is reasonable to assume that the entire time Heywood Floyd is on the surface of the moon as depicted in this film is only a few hours, an Earth day or two at most. Further, it is important to note that the Earth is frequently seen in the background in many exterior, and at least one spacecraft interior, shots in this sequence, thus it can be safely assumed that all fictional filming locations are on the tidally-locked near side of the moon, the face we always see from Earth. Also, keep in mind it takes over three weeks for the moon to orbit the Earth, thus no significant change in the "phase" of the Earth as seen from the Moon should be observable within even as much as a couple of Earth days. So, it is beyond curious that in successive shots in which the Earth is visible, it is alternately lit by the Sun, sometimes from camera left and sometimes from camera right. These are simply and inescapably errors made in the production which could have been avoided if adequate attention were given. The final shot before the cut to the Jupiter Mission is simply absurd. After showing sunlight bouncing between left and right of all scenes, and the Earth always low in the lunar sky, suddenly, looking straight up from the bottom of the monolith, the Sun is directly above and the Earth very nearly so. A pretty composition, but one which cannot be reconciled with the relative positions of these large bodies depicted immediately before the jump cut.
Jupiter Mission:
For the remainder of the film, I can mostly leave any other observable oddities to artistic license. I will note that the portions of the spacecraft that are in shadow would be in very dark shadows with virtually no hope of being photographed without supplemental lighting, and even the lighted side, at this distance from the Sun, would be very dimly lit, but that wouldn't be very nice looking, so, artistic license. I will also note that the side of the antenna array directed towards the sun keeps changing between the front and the back, with no explanation. Finally, the size of the pod bay and the pods, and the size of the circular habitat area, all of which are supposedly inside the spherical front portion of Discovery One, don't seem to be able to fit. I have yet to see diagram that makes sense of the internal use of space.
Beyond The Infinite:
Once Dave leaves in his pod the final time, to the end of the film, much if not all of what is shown is more allegory than literal, so just enjoy the ride and look forward to reading the book.
Finally:
I apologize for my gross inconsistency in the use of capitalization, but I am just too lazy to go back and fix it. Go figure. Oh yeah, and it is really worth the trouble to watch "Jupiter and Beyond The Infinite" while listening to "Echoes" by Pink Floyd, instead of the original audio, especially the quadraphonic mix, if you can get it. It is almost exactly the correct length, and this may not be a coincidence, but that is a whole other story.