Pop quiz time: What’s your display’s aspect ratio?
For an eternity (at the 3x or more speed of computing life Vs real-world life) display screens for Windows have had an aspect ratio of 4:3 (ratio of width to height, in pixels). Like 640 x 480, 800 x 600, 1024 x 768, etc.
Standards?
This is the same aspect ratio that has been the standard for U.S. television. And it was inherited from film, because TV was designed to easily broadcast films. The movie industry then developed various wide screen modes to differentiate themselves from TV.
Naturally web images and web pages have long been created at that 4:3 aspect ratio.
Squashed circles
After getting a new 22″ LCD (Liquid Crystal Display) monitor, I noticed that a perfect circle I had created in Photoshop on my old monitor didn’t look round anymore! As a guy whole builds web sites, does 3D modeling and 3D scenes, digital art, etc., I have to keep my displays calibrated accurately, so this wouldn’t do at all.
When standard change
A bit of research showed that the latest standard for TV, “HDTV” uses a 16:9 aspect ratio. Notice that this is a convenient conversion from 4:3. It’s 4 times the width and 3 times the height of 4:3, making automatic conversion easier when that’s necessary.
The problem
When I got my new larger large monitor, I decided to go from my old screen resolution of 1024 x 768 up to the next major step of 1280 x 1024 – big mistake! Little did I realize that this would take me from the tried-and-true 4:3 aspect ratio to a new 5:3 aspect ratio. No wonder my old circles were not circular! Also, there is a “wide” switch on my new monitor for watching movies and such – have to be sure that’s off for normal work.
Makers of laptop computers have been producing displays to support an HDTV 16:9 aspect ratio for some time now and they are popular. Imagine my surprise to find that my new desktop monitor was also defaulting to 16:9, out of the box!
A fix
Further research showed that I could easily get back to a 4:3 ratio by changing my screen resolution from 1280 x 1024 to 1280 x 960. That’s because I built my current main computer with a very nice nVidia N9600GT display card. Your computer may not offer a 1280 X 960 setting. And, of course, this could all be something you don’t care about at all.
Resources
I notice there is all kinds of online info about setting display brightness, contrast, gamma and color – but very little about display geometric distortion. There is a discussion of film and TV aspect ratio standards on Wikipedia. And another on computer monitor aspect ratio standards (this one has a handy table of resolution settings Vs aspect ratio).
Here is an online formula, if you ever need to calculate ratios in Excel (not a built-in feature, at least in my 2003 version).
Your own display geometry calibration
Test pattern for display geometry are more difficult to find than other types, but here’s a test pattern you can use to measure your screen display to be sure the horizontal Vs vertical dimensions of a circle or perfect square actually match up. Some monitors do have a built-in geometry test pattern, so you won’t need that test pattern. Be sure to measure with a physical device (ruler, etc.) not a software “screen ruler”.
Adjust your display height and width sizes using your display’s buttons, not using Windows. I can’t give specific directions because display monitors differ. But don’t do it until the screen resolution is set for the correct aspect ration in Windows. When you change the display sizes, you typically have to also change the horizontal and vertical position – since they interact.
To set Windows display resolution
Do [right-click on your desktop background (not on an icon) > properties > Settings > screen resolution slider].
Please feel free to comment below…
‘Til next time, here’s to real square computing…
_jim coe
About Jim Coe