National / Media | MEDIA MIX

No clear picture on 4K and 8K display differences

by Philip Brasor

Contributing Writer

One of the consumer items that enjoyed a bump in sales prior to this month’s sales tax hike was TV sets, specifically those that feature 4K and 8K displays. In many cases, it simply appears the timing was right. Many households hadn’t bought new televisions since the introduction of digital terrestrial broadcasts in 2011, but there’s also next year’s Tokyo Olympics to look forward to in glistening ultrahigh definition.

Nevertheless, there is still some confusion over the difference between 4K and 8K displays. Obviously, 8K picture quality is better and so is the sound, but why are 8K displays being pushed onto the market when 4K displays were introduced so recently? Several weeks ago, I was at NHK to talk to an executive about the public broadcaster’s upcoming promotion of 8K technology at an industry convention in Europe. NHK is the only broadcaster in the world right now with a fully dedicated 8K broadcast channel, since the technology was chiefly developed by the public broadcaster. TVs with 4K displays were developed by a number of international players.

The Olympics certainly had a role in prodding NHK to get 8K out there as soon as possible, but the public broadcaster, which also has a 4K channel, wants to stay ahead of the curve. All the major commercial TV companies in Japan launched satellite 4K channels last year, but only NHK has an 8K channel. Apparently, commercial stations need to improve their 4K technology before they move on to 8K, and they’re having a difficult time of it.

A series of articles in the Asahi Shimbun in August discussed a matter that had yet to attract much attention: A home electronics retailer received complaints from people who had purchased 4K TVs who claimed that their picture was too dark. In its investigation, the Asahi Shimbun talked to manufacturers who said the problem also had more to do with the 4K broadcasts themselves, but NHK broadcasts were less frequently the subject of these complaints. Instead, there seemed to be issues with how commercial broadcasters present their 4K content.

A reporter from the Asahi Shimbun carried out a test in May. He compared an image on a 2K display to one on a 4K display, both by the same manufacturer and using the same display size. He watched the same news shows broadcast on both 2K and 4K channels, and in “standard mode” found that, indeed, the 4K images were noticeably darker than the 2K images. When the brightness setting was turned up to maximum on 2K and 4K displays, the difference was less obvious, but at that point he couldn’t tell if it was a problem with the device or a problem with the broadcast.

The improved picture quality on 4K displays is due to the simple fact that a 4K screen has four times as many pixels as a 2K screen, and the number of colors that can be reproduced is larger. More significantly, greater contrast is achieved, meaning darker blacks and brighter whites by a factor of more than 10.

According to an expert interviewed by the Asahi Shimbun, part of the darkness problem stems from a mismatch between the capabilities of the broadcast and the capabilities of the device. 4K broadcasts use the highest brightness setting but current 4K TV sets can’t quite reproduce that intensity. 2K devices make up for their limited brightness with backlighting, but if you incorporated backlighting into a 4K display you’d lose the overall contrast benefits.

Thus, the darkness problem would appear to be the manufacturers’ fault, and, seeking answers, the Asahi Shimbun reporter contacted the five main TV makers in Japan. Four of them said they don’t talk publicly about brightness, with one commenting that they “didn’t compete” in terms of brightness and another saying that brightness is “determined by many factors.” A Toshiba representative admitted that the cost of boosting the brightness of a 4K set to its limit would make the cost prohibitive. Of course, the technology is improving, and manufacturers are gradually solving the brightness problem without adding too much in cost but, as of June, nearly 7 million 4K TV sets had been shipped, and the implication is that these devices may already be obsolete.

But maybe it’s more than the TV set. When proper 4K cameras are used to record or transmit proper 4K broadcasts there’s usually no problem, but when 2K cameras are used for 4K broadcasts, the resulting images are dark. NHK has no problem in this regard because it helped invent the technology and all its 4K and 8K content is made with corresponding equipment. However, commercial broadcasters have to adjust the transmission depending on the type of camera used since their 4K channels also have advertisements, and they may be prohibited from adjusting images. Consequently, the program’s specifications may be set to that of the commercials’, meaning the overall picture quality could be degraded.

The question no one seems to be asking is: Why obsess over these 4K problems when 8K is already here? For one thing, the amount of data needed for 8K broadcasts is huge, so satellite broadcast technology is not the ideal means of transmission. NHK told me that when 5G networks become widely available, 8K will make more sense because 5G can handle huge amounts of data. More to the point, 4K and 8K satellite broadcasts require special tuners and dishes. Why go to the expense of buying new stuff when 8K will someday extract images, sound and data from your already installed 5G internet connection?

The upshot of the Asahi series is that there is no satisfactory advice for people looking to upgrade to 4K, or even 8K, for that matter. And maybe it’s not important. After all, it’s common knowledge in Japan that only older people still watch television anymore, at least on TV sets, and that both 4K and 8K can only be fully appreciated on very large displays. Young people, if they watch TV at all, tend to watch it on their smartphones or tablets. The future of TV will depend more on content than it will on devices.

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