Once television shifted from analogue to digital the road was open to increase the image resolution. From the analogue systems based on 576 or 480 lines (both having 720 dots per line) we moved to Full HD at the end of the last decade and now we are seeing more and more UHTV (4K) being sold. It is not the end of the game! On the market we are also starting to see 8K television (7680×4320 pixels) with an exponential resolution increase:
- NTSC: 720×480 > 345,600
- PAL: 720×576 > 414,720 (20% increase)
- HD: 1920×1080 > 2,073,600 ( 500% increase)
- 4K: 3840×2160 > 8,294,400 (400% increase)
- 8k: 7680×4320 > 33,177,600 (400% increase)
- 16k: 15360×8640 > 132,710,400 (400% increase)
Notice that it is not just a matter of “squeezing” more pixels per inch. As you make pixels smaller to have more of them in an inch (thus increasing angular resolution, the only one that matters to our eye!) you also have to compensate for luminosity, brightness. If all remains equal, the more you shrink a pixel the less light it will be emitted. Moreover, since there is a separation between pixels, i.e. an area where no light is emitted, the more pixel you squeeze the less luminosity you get. 4K television became possible thanks to the increased luminosity technology made possible on each individual pixel.
It is not just about pixel size and luminosity. The more pixels you want to use, the higher the bandwidth needed to activate all those pixels. This is where the new Display Port 2.0 standard comes in.
The new standard supports transfer speed of 70Gbps that allows the use of 16k monitors. In conjunction with the USB 4 type C connector (designed to support speed up to 80Gbps) it paves the way to run 4 8k screens that you can buy today and place on the wall like tiles to form a giant 16k television.
Real 16 k televisions will probably arrive in the second half of this decade (we have seen a 400% increase in screen resolution every 4 to 5 years) although through 16k content may be further away.
The interesting thing is that you may not need 16k content to perceive the beauty of a 16k screen.
Actually, there is very little content today transmitted in 4k resolution (although it is growing on YouTube and Netflix). Yet, you can appreciate the better image delivered by a 4k screen even when it is fed with HD content. The magic is delivered by “AI” (sort of, but marketeers love to say it is AI doing the trick). Basically, your television hardware and software is smart enough to analyse the HD images in real time and “add” content (pixels) to create a higher (although fake) resolution image. It is so good, actually, our brain does not realise it is seeing a fake image, it feels perfectly ok and way better than the HD!
Same trick is used to upscale the resolution on 8k screens. Obviously, the upscale is much better if it can start from a 4k content! We are likely to see the same trick being applied on future 16k screen.
Now, isn’t this amazing? It used to be that professional equipment was providing higher resolution and our consumer equipment (television) was using just part of that to keep the television price affordable. Now it is the other way round. Our consumer equipment is “better” than the professional one and software inside our television takes care of the upscaling.
The question is, of course, is this rush towards higher and higher resolution makes any sense in quality perception. Well, the perception of quality is quite complex because it depends on the physical characteristics of an image (flow of images) but it is mediated by our eyes and eventually decided by our brain.
The perception emerging in our brain is the result of million of years of evolution where the image processing has been contextualised. The perception depends on the resolution of our eyes, that in turns depends on the luminosity and luminosity range of the scene (contrast) plus the flow of images resulting from the saccadic movements plus our body movements. This si why when you ask what is the maximum resolution that can be perceived you get so many different answers (besides, what matters is the angular resolution and this depends on the distance from the object).
For sure we can imagine a future where our walls can actually be screens and at that point 16k can make sense.