Valerian was a really pretty movie.
A lot of it was also entirely or partially computer generated.
The finer points of computer animation can be very complicated.
For example, you will often end up with visible outlines at the boundaries between CGI objects and the background they're composited with.
And many modern computer animation and compositing programs actually allow you to do things like add fake motion blur to CGI elements so they exactly match the live video you're adding them to.
Many computerized processes for sharpening pictures also actually work by adding bright and/or dark halos around the edges of the objects being processed - which produces a sort of optical illusion of being sharper.
(It's called "unsharp masking" - which name comes from how the process was performed back in the days of actual film.)
Compared to the color space used for a Blu-Ray disc, HDR allows for brighter whites, darker blacks, and more fine levels of distinction in-between.
Each of those offers certain benefits - but only under very specific conditions.
For example, assuming you were to start with a video that had been filmed with a camera that was "every bit as good as what a Blu-Ray disc could store" in terms of brightness, contrast, and color.
If you were to put a new copy of that same video on an HDR disc - it would look exactly the same.
(If a Blu-Ray disc could reproduce it perfectly already - then HDR can't really improve on that.)
In order to take full advantage of those benefits you need to start with an original that is "better than what fits on an ordinary Blu-Ray disc".
If it's a big budget movie, they may actually re-film some scenes, or process the original masters more carefully to extract more range and detail.
If there are computer-generated elements, the originals may be replaced by newer versions, re-created from the original data at better detail levels and greater color depth.
And, yes, there are very sophisticated software programs that can actually make real improvements to existing images - usually with lots of human supervision.
(And, if they do a sloppy job, or push things too far in an attempt to make it look impressive, the result may end up being worse.)
Normally, when a movie or video is produced, certain precautions are taken to avoid situations that won't look good on film.
You don't point the camera at something that's too bright "because it will blow out"...
And you don't film in really dark places "because you won't get any black detail so you won't see anything very well"...
HDR moves these boundaries further out... which improves the situation at many different levels.
The benefit of the increase in the bit depth can be even more subtle... and you tend to not notice it unless you're looking for it... and under very certain conditions.
For example, a standard "24 bit color space" can show 10 point something billion colors - which sounds like an awful lot of different colors.
However, all of those colors are merely combinations of 256 levels of red, 256 levels of blue, and 256 levels of green.
Let's say you have a picture of a big pure bright red ball with a light shining on it.
That ball is really bright in places, and really dark in others, but it's red all over.
Since your ball is pure red, with no blue or green in it, out of all those colors, you're only going to be using the 256 shades of red to reproduce it.
And, if it's a really big, really smooth ball, you might actually notice some banding because you don't have ENOUGH subtly different shades of red to make it look smooth.
Look at a scene that features a long steady shot of a setting sun... a big smooth bright orange ball.
There's a good chance that, on a regular Blu-Ray, if you look closely, you'll notice banding, because there aren't quite enough different shades of "bright orange" to color it smoothly.
However, on a well-produced HDR disc, you'll have a lot more shades to work with, so the resulting image will look smooth, with no banding.
Or look at a really dark scene.....
It ranges from dark in places to really dark in others - and is basically black and white.
As a result, out of all those possible colors, your Blu-Ray disc may have to reproduce that scene using only a few dozen shades of dark grey.
And, if you look carefully, on a TV that can reproduce it accurately, you'll notice splotches and patches where one shade of grey meets another.
However, on a well-produced HDR disc, there will be a lot more shades of dark grey to work with, so the picture will look smooth, with plenty of detail in the very dark areas., and no bands or splotches.
In general, you will see this benefit in areas where there is a large area, made up mostly of a single color, but with very slight variations.
In these situations, you will often see at least some slight banding or splotchiness with a Blu-Ray disc, and it won't be there on the HDR version.
(But, in many cases, you wouldn't notice the difference, unless you were specifically looking for it.)
Of course, those cool HDR demo scenes are very carefully designed to show off these differences, but they may not be nearly so obvious with an ordinary movie.
(And they are even less likely to be obvious with an older movie - where the director and recording engineer actually tried their best to avoid situations that wouldn't look good on a Blu-Ray disc.)
I'll give you an easy and fun example.....
Start looking at old TV shows, and on DVD and Blu-Ray discs, for things that are colored bright pure purple... like sparkly amethyst jewelry.
You won't find very many... because it's a well know fact that, due to various limitations, older TV gear didn't do a good job of reproducing a bright saturated purple color.
(However, you'll see a lot more of that color appear in modern HDR movies, because HDR reproduces it quite well.)
What everyone needs to remember is that not all video is of especially good quality - and bad 4k video is still bad.
I recall one of the later Transformers movies (I forget which one now).
I initially saw it on Amazon Prime video - and was disappointed at a lot of noise in a few of the outdoor low-light scenes (there was one dialog that took place outside a barn that was especially bad).
I assumed the noise was an artifact of a poor quality transcode for streaming.... and really looked forward to when the 4k disc came out.
Guess what?
When the 4k UHD disc was finally released....
It still had the same high noise level... in the same scene....
But, yes, the computer generated graphics scenes on the Transformers movies are really impressive in 4k.
Another thing that I've only seen mentioned in one or two articles is how well 4k and HDR handle specular highlights....
Those are the little really bright pinpoints of light that make metal objects look shiny and things like glitter and tinsel look sparkly.
Even if you don't notice the smaller details in normal objects... 4k does better with specular highlights... so shiny metal looks more like actual metal and glitter and tinsel really sparkle.
You'll also notice it on pictures of sunlight glinting off the tips of ocean waves and things like that.
It's something you may not consciously notice until you look for it... but it's one of the reasons why "things really do look better when they have more detail than you think you need".
Also bear in mind that many people actually LIKE film grain... and it is actually often artificially added to many movies shot on video to "make them look like real film".
KeithL I am starting to realize that there is a variety of quality for 4k and a lot of it has to do with the orignal source material. I had a question regarding spectral highlights. I don't understand why the picture that I'm seeing on UHD disks in terms of "HDR" stuff isn't already possible on Blu Ray discs. The lights while bright and all don't look all that unreasonable to actually have encoded on to a regular Blu Ray picture. Is there something I'm missing?
I just watched Mission Impossible Fallout UHD. I am quite familiar with the blu ray version of this disc remembering it looked quite nice. On UHD it was a mixed bag.
The widescreen parts of the movie done indoors had an awful looking filter on the lense and lots of noticeable grain and (bad blurry) glare. It looks like this was intentional but a real pity because it ruined what could have been outstanding high resolution takes. The master was from a 16k IMAX camera (which really shows) and a 35 mm film camera (which unfortunately also shows ).
Interestingly the UHD encode showed peaks of 80-90 mbps even on these rather low res scenes.
Then the IMAX scenes were breathtaking but unfortunately there were only two main IMAX scenes both which looked great. I don't understand why the bike chase, the car chase, and the bathroom fight scene weren't done in IMAX and I finished the movie feeling shortchanged simply because the IMAX wasn't fully exploited.
Transformers 2 Revenge of the fallen which was a 2k master was despite its 2k mastering was tons of fun. For all the shade thrown at the Transformers franchise almost all the films nailed imaginative sci-fi action that was tons of fun and kept you watching. Any scene with Optimus Prime fighting was guaranteed to be amazing with a really thrilling sense of motion and action all around. Only wish I had for the 4k version was that I wish they had done even more with the spectral highlights - most of which were red.
Valerian City of a thousand planets - here is a movie that appears to be beg for an IMAX presentation but has none. However it doesn't detract that the quality of the picture here is excellent and pretty much exactly what I wanted from an UHD disc. Colors, clarity, detail all there. Some interesting things I learned here by pausing frames, for some blurry fast moving shots, it looked like they had gone in and touched it up. I noticed black outlines on some fast moving parts of the picture when paused frame by frame and even some sort of computerized smoothing in the blur. I suppose the black outline is some version of black frame insertion but it was used only around parts of the frame where there was fast motion rather than the whole frame. The effect worked well producing a cleaner sense of motion. In the end 24 fps imo really lets down the viewer. There's only so much that cinema makers can do with a 24 fps limit in terms of motion. We need to shift up to 60 fps yesterday.