Why We Always Want More From Displays
The other day, I spotted an article about the differences between a MacBook Pro and a MacBook Air. I clicked on the link as my Mac mini is four years old. I’m starting to think I might want something better and at the moment I use an iPad Pro for mobile computing. However, I really don’t like iPad OS and would much prefer the MacOS so have been thinking about changing from a desktop to a notebook as my main machine, Before the Mac Mini, I had used top of the range Lenovo notebooks for many years.
Anyway, the writer of the article was bemoaning the lower quality of the display on the MacBook Air compared to the one on the Pro. That’s a fair point, but the writer describes the MacBook Air as ‘low brightness’. What amazed me was that the brightness of the Air display is 500 cd/m2 (nits). That’s less than a high end TV, but the same level as the Dell XPS 13 notebook, for example, and brighter than the Dell Pro 13 Premium Laptop.
Further, the MacBook Air has P3 color support while Dell supports sRGB, a smaller color gamut. It’s a rule of thumb that increasing the color gamut of a display reduces its efficiency and its brightness, so the MacBook Air is doing well to match Dell, but with a better gamut. It doesn’t make so much difference for accounting or word processing, but P3 is better for video as it is the color gamut used by DCI, the Digital Cinema Initiative.
(I have used Dell as an example as they are very conscious of display quality (they have the biggest monitor brand globally), and even have a web page devoted to 500 Nit laptops. When I checked the HP site, the specifications were less clear).
The State of the Art Not Long Ago
Just to put this in context, the first 500 cd/m2 notebook was only released less than ten years ago. 150-200 cd/m2 had been the standard for many years even on desktop monitors. At the same time, most laptops over the last 20 years have had support for much less than 100% even of sRGB, let alone support for P3. 70% coverage of sRGB was quite normal for a long time in notebook displays.
So, I hope I have established that the MacBook Air actually has, arguably, a top quality display. (and is widely expected to switch to an OLED display next year to be even better looking, still)
But the MacBook Pro…
The main thrust of the Medium article was that, after you see the 1,600 cd/m2 (peak)/1,000 cd/m2 (full screen) of the miniLED display on the MacBook Pro, it’s hard to go back. It supports P3 as well. Further, the resolution is 3025 x 1964 – around 6 million pixels compared to the Dell XPS which is 2560 x 1600.(about 3.7 million laptops). As with more color, more resolution in LCDs always means more power or less brightness.
(As an aside, the author found a paper that Apple had presented in 2019 that explained some of the details of its miniLED technology and has no doubt that a lot of clever engineering has gone into the products that use it)
And this is the point. The writer has been in the display business since before IBM had a PC. In the early days of the PC, in 1984, IBM had a special ‘Ultra High Definition’ system with the Professional Graphics Controller (PGC) and a matching display. That graphics board alone cost $4,290 in 1984. That’s $13,000 today – and that was just for the board. (and that puts the price of modern GPUs in perspective!) The monitor was extra. However, the board only supported 640 x 480 with 256 colours. That was very high resolution then.
Bob’s Second Law
By the time I had been in the industry for a few years, I realized that at any one time, nearly everybody thinks that what we have today is ‘good enough’; ‘You really don’t need more’. However, that only works until you see the next thing. So 500 cd/m2 notebook displays looked great when we were used to 200 cd/m2. But they stop looking so good when you have seen a 1,600 cd/m2 model.
In the final analysis, a display is a communication system that is sending visual information into a brain, via the viewer’s vision and perception system. Like any communication system, until you saturate the amount of information, there is always a good reason to get more bandwidth.
As that chap Moore had a law in his name and so I thought I should have some. So I came up with Bob’s Second Law* to explain this phenomenon,
Everything that Increases Visual Bandwidth Wins (in the end)
This is the trend that has driven display performance, whether color or dynamic range or brightness, frame rate or resolution. That’s why the 8K Association exists. As Dr Masaoka at NHK established some years ago, for viewing a large screen, humans need 8K if you want them to think they are seeing ‘reality’.
* Bob’s First Law was that “Everyone that buys a computer always buys another”. I think that has been true for at least forty years.
Apple should be up grate the iPad Pro to be 8K and Thunderbolt 5 too! So far they minimal up grades every year are mean nothing to step forward with technology!