2001: A Space Odyssey is presented on 4K UHD courtesy of Warner Brothers Home Entertainment with a 2160p transfer in 2.20:1, and already that aspect ratio should be an early tipoff that things are definitely "new and improved" from the long ago Blu-ray release. As is documented in an actually fascinating two page "history" of the restoration provided by Warner's Stuart Herriott for this release, "the 2018 release contains correct picture aspect ratio as it was scanned directly from the 65mm original negative which is spherical (flat) versus anamorphic (scope). The 35mm anamorphic (scope) reduction that was scanned for the 2000 and 2007 releases contained a little more information on the left and right of the frame then [sic] was intended for 2.2 70mm projection aspect ratio. Also, the optical scope reduction added a slight amount of linear image distortion, which is not present in the 65mm spherical camera negative." Mr. Herriott's detailed accounting of the long and involved restoration process, which Mr. Herriott traces back to photochemical work begun in 1999 (if I'm understanding things correctly) makes it clear that Warner, typically a commendable curator of its catalog, has approached this title with the care and handling that it deserves, and those who were fearful of Christopher Nolan's perceived "revisionism" can probably relax. So, with that out of the way: how does the darned thing look? Pretty spectacular in sum, though as Mr. Herriott also gets into, those who are going to utilize previous home video releases as the standard against which this release is measured may quibble with some aspects, notably the color timing, which is noticeably different in some respects from previous releases. As Mr. Herriott mentions, "audiences may be most familiar with previous home video releases. . .and may be struck by some of the differences. However, the newly remastered version has been scanned and timed to directly match the original film release, rather than the previous home video master." Some of the most noticeable differences happen right off the bat in The Dawn of Man sequence, where there's a slightly more desaturated look, with a brighter overall ambience that tends to make skies paler. But there are some interesting new changes here, albeit often on minor things like the weirdly mid(21st?)century modern chairs on the space station, which have a kind of crimson tone to them now. Restoration efforts have also eliminated some of the projection effect anomalies that were prevalent in previous versions, and I frankly noticed none of the admittedly minor speckling and dirt that were in evidence on the previous Blu-ray release. Detail levels are superb throughout the presentation, and there's a nicely organic looking grain field, one that spikes expectedly in many of the optical effects, but which resolves without any issues whatsoever. Blacks looked solid and (for those who may have feared) unboosted, and the entire palette looks appealingly saturated, and what Mr. Herriott terms as "luminance and color" dropping at the sides of the image on the older version has been eliminated. The psychedelic climax is bold and vivid and certainly better detailed than I remember seeing in 35mm reduction prints.
The 4K UHD presentation takes an already stellar (sorry) 1080p Blu-ray and delivers even more fine detail and (especially) shadow detail, as well as an often spectacularly suffused palette. I noticed all sorts of new information watching the film in 4K, much of it admittedly minor things like some of the information on the displays in the Discovery One, or even some of the background set dressing in the pod that Dave and Frank think they're "hiding out" in. Fine detail remains remarkably intact even given some of the rather severe lighting, especially reds, that suffuse so many of the space set scenes. In fact, one of the "reddest" scenes, the "decommissioning" of HAL, offers really superb fine detail on Dave's face, this despite not just the slathering of red hues, but the fact that he's in a space helmet. Other "helmet" based items like the sudden aging Dave is subject to in the big finale are also noticeably more detailed. Grain is finely resolved throughout this 4K presentation, appearing arguably a bit more variable in terms of intensities and thickness than in the 1080p version. The palette attains some really interesting new highlights courtesy of Dolby Vision. The opening Dawn of Man sequence has a kind of gray-sepia tone in this version that isn't quite as prevalent in the 1080p version, but some of the later sequences, like Dr. Floyd arriving at the monolith on the moon, almost mimic black and white films for a moment or two, with an emphasis on silvers and grays. As mentioned above, the incredible reds scattered throughout this presentation were one of the most memorable elements of the 4K presentation, and the whole final hallucinogenic ride through the lightshow and then the weirdly altered landscapes are also better detailed now, with an incredibly vivid (if weirdly skewed) palette. Younger viewers more used to digital capture may feel this is soft at times, a kind of ironic reaction to the incredible detail a large format offers, but those who have seen 2001: A Space Odyssey projected and want their home media to replicate that appearance will most likely find this a very enjoyable and worthwhile viewing experience.