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| 20th December 2010 | ASPECTS OF LIFE |
Brian Grainger
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The aspects I am talking about in the title, (apologies to Andrew Lloyd Webber), are aspect ratios and those of computer monitors and TVs in particular. This year I have been buying a new computer system and I started off with an LCD monitor. My previous system had a standard 17" CRT with 4:3 aspect ratio. I also have a laptop with a 15" 16:10 aspect ratio, which I found quite good for viewing video/DVD. At work I had, at one time, a 19" CRT with 4:3 aspect ratio but that was changed a little while ago to a 15" LCD monitor with an aspect ratio of 5:4 (??). Of all these, my poor eyes really liked the 19" CRT but you cannot get a 4:3 aspect ratio LCD screen from the High Street very easily. What to do? I basically made a choice based on the manufacturer I wanted to get, Iiyami, what was available in my local dedicated computer shop and what I was prepared to pay. I ended up with a 22" screen with an aspect ratio of 16:9. 22", I thought, that should be as good as that 19" CRT. When I finally got the rest of my computer system and put it all together I soon realised that the new screen was not as pleasing as that 19" CRT. I decided to search the web to find out why and what I should have done before buying a monitor. I am writing this so that others may have the benefit of my investigations and are fully cognisant of all the issue BEFORE they buy a new screen! In the days before digital TV and digital monitors things were straightforward. Virtually everything had an aspect ratio, the ratio of the image width to its height, of 4:3 (or 1.33:1). The only time you saw anything different was when you went to the cinema and perhaps the most remembered widescreen format was CinemaScope of 2.66:1. When these films came to be broadcast on TV it became slightly awkward. Either they were zoomed, with possible stretching in a vertical direction, or they were displayed in a letterbox format making some of the TV screen black and wasted. Computer screens were essentially the same as TV cathode ray tubes and they maintained the 4:3 ratio. Many the time, when writing documents, I have wished that the A4 standard in portrait mode was available for computers. In the digital age all things changed. The 16:9 aspect ratio has become the international standard for digital TV, whether high definition or otherwise. As computers have become more akin to multimedia centres, (at least in the home market), it seems manufacturers have latched on to this and wide screen LCD screens are the norm now. Actually, they may have had their own interest at heart, rather than the consumer, as I will show in a minute. When I did not find my new monitor as pleasing as expected my first thought was where did this 16:9 ratio come from. The following page from Wikipedia was most illuminating: 16:9 was chosen because all the common formats at the time could be enclosed by this shape with the minimal use of black space. One thing to note, from the diagram on the wikipedia page, is the height of the 4:3 window determines the height of the 16:9 window. We shall see that this is quite important! The Wikipedia page also put forward another reason why LCD manufacturers might prefer 16:9 format to 4:3. Whereas CRT screens were cheaper to produce the more square they were, with LCD screens it is the AREA that is important. The smaller the area the cheaper the screen. Since screens are sold in sizes based on their DIAGONAL length one can create a 16:9 format screen in a much smaller area that a 4:3 format screen with the same diagonal. Maybe manufacturers are trying to give the illusion of big screens while keeping their eye on the bottom line all along!
As a consumer, the question is what do WE consider better for viewing - viewing area or the viewing height of a traditional 4:3 TV. There is an excellent web page which discusses this point and explains why viewing height is the key. It can be found here: This is also the reason to why I was not totally satisfied with my new 22" screen. I had expected the screen height to be similar, if not more than, the 19" 4:3 screen. It wasn't. It was nowhere near it. In fact the height of the 22" screen is only slightly more than the 17" 4:3 which I have been using for the past 12 years. This is a pretty sad admission from a Chartered Mathematician who knows all about the Pythagorean Theorem, but I just didn't think about it, or its implications, when buying a monitor. A side issue, which also contributed to the lack of screen height was that the screen diagonal was not exactly 22". It was 21.5". I only found this out when I read the specification in the instruction manual. Perhaps I should sue under the trade descriptions act. I hope these words will warn those who are intending to purchase their own screen and enable them to do the necessary work before buying. It is even more important in the case of TV, because the screen height determines how far away you can be seated to see the TV comfortably. If you don't want to spend time rearranging your lounge, make sure the height of your new widescreen TV is the same or bigger than your old 4:3. The web page referenced above gives an 'aspect ratio' calculator to compare widths, heights and aspect ratios. However, a picture paints a thousand words and the following page gives another calculator, enhanced with graphics, to compare alternative sizes of monitor: This site told me that my 21.5", 16:9 screen was equivalent to a 17.5", 4:3 screen and it was pretty obvious from the two images that comparing with a 19" 4:3 resulted in loss of height. Although I got a surprise with my new screen it will, of course, be much better for viewing widescreen TV or DVD than my old monitor. I have also found that I now have the capability to rotate the computer desktop through 90°, (a feature of Windows 7 maybe?). I could quite easily view an A4 page of type if I rotated the screen. Unfortunately, the stand does not allow rotation. Maybe I will be investigating wall mounting brackets that allow rotation next!
x / 1 = (1+x) / x x^2-x-1=0 x = (1 ± sqrt(5))/2 Finally, let me deviate from the plot slightly and introduce another aspect of life. As a mathematician I have long known about the Golden Ratio. If a line is dissected so that the ratio of the line length to the length of the longer section is the same as the ratio of the longer section to the shorter section, then the ratio is known as the golden ratio. A bit of mathematics will show this to be (1+sqrt(5))/2:1 or a little over 1.618:1 The Golden Ratio keeps popping up in loads of places - in mathematics and nature. It is said that rectangles with width to height in the golden ratio are most pleasing to the eye and that many works of art are thus painted on a 'golden' rectangle. Why do I mention it here? Well that laptop I have, with its 16:10 aspect ratio, is as close to golden as one can get. No wonder I find it pretty pleasing. Maybe 16:9 was not the best for a standard after all. |
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