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How Does Screen Resolution Work?

I’ve not received this exact question, but rather, I get a lot of questions relating to screen resolution and why things don’t work as expected. I also get questions where changing the screen resolution is one possible answer, but explaining why gets … complicated.

Screen resolution seems like a very simple thing and most of the time, it is.

The problem is that sometimes it’s not. And it’s not in a way that let’s me say “smaller is actually bigger” with a straight face.

Yes, making things smaller can make things bigger.

Told ya it’d be complicated.

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We’ll start with your computer display or screen, or as it’s more commonly called the “monitor” (because in the old days, it was where computer operators monitored the operations of the room-sized computer).

Your monitor is comprised of “pixels” – individual dots – that are arranged in a rectangle.  Each is one point of light and that one point of light is capable of being a color – any of hundreds of thousands or millions of different colors, in fact.

The dimensions of the rectangle of pixels on your monitor is its maximum resolution. For example, the monitor that I’m looking at is 1920 pixels wide by 1200 pixels high – a little over 2.3 million pixels:

1920x1200 proportions

Windows, of course, allows you to configure the screen resolution that it displays as. This is independent of, but limited to, what your monitor is actually capable of. For example, attempting to display something larger than 1920×1200 on my monitor will likely result in no output at all – my monitor is incapable of displaying anything larger. (Your video card represents an additional limitation, but I’m explicitly ignoring it here, assuming that it is more capable than your monitor, which is frequently the case.)

The ideal setting is typically to set Windows to display at your monitor’s maximum resolution.

Windows XP displaying at 1920x1200

This is the ideal setting because as we’ll see in a moment, there’s no scaling or stretching. Your monitor has exactly one pixel at each point Windows is expecting there to be one. The monitor’s physical characteristics match what Windows is attempting to output.

So far, we’ve seen that the ideal setting for most is to match your monitor’s capabilities exactly and that if you try to display something larger, in terms of pixel count, then you may get nothing at all.

What happens if you display something “smaller” in pixel count?

I’ll use 1024×768 as my example:

1024x768 Proportions

When you use Windows at this resolution, things get more cramped:

Windows that were, perhaps, 1000 pixels wide now take up most all the available space on the screen.

When you attempt to display 1024×768 on a monitor capable of larger resolution, like 1920×1200, several different things can happen.

Centered: the 1024×768 display that Windows is trying to create might be centered in the 1920×1200 physical screen:

1024x768 screen centered on a 1920x1200 display

This will typically feel smaller, as only a portion of the displays physical screen is being used. This is fairly rare among computer monitors, but it can happen. I’ve seen it more often in older laptops, particularly at boot time when Windows attempts to display an 800×600 screen on a laptop monitor typically much more capable.

Proportional Stretch: the 1024×768 display is stretched to fit the physical area, but while maintaining the original ratio of height to width (the “aspect ratio”):

1024x768 screen stretched to 1920x1200 maintaining aspect ratio

This is extremely common behavior for monitors that are asked to display a resolution less than their maximum.

One thing to note, however, is that sometimes what’s on the screen can seem somewhat fuzzy. The issue is that what was intended to display as a single pixel on, say, a 1024×768 display is now “stretched” over more than one to expand into some portion of the 1920×1200 monitor. Depending on the specifics and how you calculate it, this example attempts to stretch one pixel over about 2.4 pixels. Because partial pixels are impossible, fuzziness results.

Perhaps the most remarkable point, however, is the most confusing: Because the smaller image has been stretched to fill a larger physical area it appears larger. Compare the Internet Explorer Window in 1920×1200 native on the left to the Internet Explorer Window in 1024×768 stretched and centered on 1920×1200 on the right:

1920x1200 1024x768 screen stretched to 1920x1200 maintaining aspect ratio

This is the part where I get to say – with a completely straight face – that making your screen resolution smaller may in fact make things appear bigger on your display.

Stretch-to-Fill: the 1024×768 display is stretched to fit the physical area, but the ratio of height to width is not preserved.

1024x768 stretched to fit 1920x1200 without maintaining the aspect ratio

What you might notice here is that everything looks ever so slightly elongated horizontally.

What’s happened here is that the image was stretched vertically, taking what was the 768 pixel height of the displayed screen to fit the 1200 pixel height of the monitor. If you apply that same ratio (3/4) to the width, you have only 1600 pixels to fit on a display that is 1920 pixels wide. Where in the prior example, we simply centered the result, displaying gray or black bars on either side. In this example, we stretched that 1600 out to 1920 without changing the 1200 pixel height. The result is that while the image fills the entire monitor, it appears horizontally elongated.

The bottom line is that “making things bigger” can mean either of two things:

  • Increase the resolution, adding more pixel to your screen and giving it a logically larger surface area as measured in pixels.
  • Increase the size of something on the screen, making it visibly bigger.

As you can see, there are many approaches and yes, making things bigger (physically) by making things smaller (in pixel count) is in fact one of them.

15 comments on “How Does Screen Resolution Work?”

  1. Interesting, but too complicated for me. I was looking for a way to make my screen images smaller. The window on my screen takes up too much space. There was no direction on where to go to improve a problem. I know, it’s a problem talking to folks at this level. But all of usdon’t fully understand computerese…but we’re trying. That’s why we read your stuff.

    Reply
    • Let me start with a little background. Until about yen years ago all monitors had a width to height ratio of 4 to 3. Example, take 640 by 480 and divide both numbers by 160 and you get 4 and 3. Note: All CRTs were 4 by 3. Then, and I hate it but it is reality, the powers that be decide to make what is called widescreen monitors. That changed the width to height ratio to 16 by 9. Now if you decide both numbers by 3 you get 5.333 by 3. Side thought: that is the normal ratio now for flat screen TVs. Notice that if you divide both of those numbers (1920 and 1080) by 120 you get 1920/120 = 16 and 1080/120 = 9. I have been wearing glasses for 58 years and they still don’t correct my vision as much as I’d like them to – my vision is 20-25 which is legal for driving – I just can’t always read the street signs so I sympathize with you. For optimal performance you have to get video cards and monitors as if you were purchasing one item. The monitor has to always accept the best resolution that the video card has to offer. Otherwise you’re wasting money on your video card. Then there’s the problem of which ports you use. HDMI, which is digital, is the best. DVI is also digital is second best – it’s not a good choice. VGA, which is analog, is far and away the worst. This means that you have to buy a monitor and computer with HDMI ports and connect then with a cable with HDMI plugs. The cables can be very inexpensive. Don’t save too much money on them. $10 is okay, but you can get them for less than a dollar and suffer the consequences. Given the cost of video cards, computer, and monitors, saving $9 on a video cable is insanity. Right-click on an empty space on your desktop and you will see what resolution it’s set to. Usually it has one of it’s many choice marked off as “recommended”, but if your video card can’t produce that setting you will have to drop down to a lesser setting on the monitor by lowering the screen resolution. By the way, video cards also known as graphics cards can run quite hot safely.

      Reply
  2. I recently learned the hard way about the “fuzzyness” an LCD monitor has when it’s not in it’s “Native Resolution”. I’m the IT guy in our office and while I’m very computer oriented, I don’t know everything. I’ve always had old CRT monitors at home and that’s what we had in the office until it was time to purchase new workstations (and monitors). Of course, all new monitors are LCD now, but for someone that doesn’t know any better, they don’t change screen resolution like the old CRT’s do and this “fuzzyness” as Leo refers to it is a result of changing them from their “native resolution”. The 22″ wide screen monitors I chose were very LONG (1920 x 1080 native resolution)…that’s almost 2:1 so a 22″ measurement makes for a really short and really wide screen. My first thought was, “No Problem, just change the resolution so all the middle-aged adults (read: bad-eyes-people) in the office can see things because like Leo said, smaller is bigger. To my surprise, the “fuzzyness” was there. *SIGH* Trust me when I say that smaller is better than fuzzy too! Fuzzy = headaches after just a couple of hours.

    Forutnately, windows has a DPI setting that can be changed to accomodate that, but it’s not the best option as very few programs (Windows and Office included) work in it at 100%. Our enterprise software is very bad at higher DPI because some clickable buttons in the windows aren’t always visible.

    The lesson: Find out what the “Native Resolution” is and THAT’S what you’re stuck with…and trust me when I say that 1920 x 1080 SUCKS if you already have bad eyes. 1680 x 1050 is a MUCH better 22″ monitor (both are called “wide screen” but the resolution will probably only be found in the “tech specs” area of the web site you shop on).

    Reply
  3. I have 2 monitors.
    Primary: ViewSonic VP920 1024×1280 Portrait
    Secondary: Acer AL1716 1280×1024 Landscape – unfortunately, it cannot be rotated.

    All play well together, EXCEPT if AOL is displayed on the Landscape monitor, it remains in Portrait width! And AOL is based on Internet Explorer which happily fills either screen. Puzzling and annoying.

    Any ideas?

    Reply
  4. Ralph Kuhn: If you right-click anywhere on your windows desktop and select properties, a new window will open. On the settings tab in that window, you’ll see the “Screen Resolution” that Leo’s article is about. Be warned though, if you have an LCD monitor (aka, “flat panel”), it’s native resolution is it’s best setting…or else you’ll have to deal with the “fuzziness” that Leo discusses and it’s inherent headaches. Also, it sounds like you want to make the resolution bigger so that your windows will be smaller…which probably won’t be available too you as the Native Resolution is usually the biggest setting on these flat panel monitors (meaning, you won’t be able to slide that little slider any futher to the right to accomplish your goal).

    HTH

    Reply
  5. Sometimes fullscreen apps work funny on widescreen LCDs. For example, one of the ones I play (a cheap budget game) will go halfway off the screen, rendering it unplayable unless you change the resolution to 800×600. I got fed up with it and found this little program called Res-o-Matic which will change the resolution when launching the program. Just thought I’d recommend it.

    Also, my graphics card is supposed to have the display scaling for widescreens, to make it less stretchy. However, due to having the wrong kind of display cable (I don’t have a digital cable) the option doesn’t show up in the NVIDIA control panel. (Does anybody know how to enable it without getting a new cable?)

    Reply
  6. Followed your advice and bumped up my laptop to it’s optiaml res., despite my middle aged eyes. It looks so much clearer and of course there is so much more real estate. I’ll just have to be content using the ‘readers’, but because of the increased clarity you spoke of, the size issue was almost a wash! Thanks!

    Reply
  7. I setted up my computer screen to the largest option there is (I think it’s 1600×900 for my computer) and I ran a program. Then I shut down my computer when I finished using it. When I started my computer again, the screen resolution was changed the the minimun (I don’t remember what it is.) Why/How did this happen?

    Reply
  8. If you want your LCD display to be an acceptable, readable size when using the native resolution just go into Windows Display Properties->Appearance->Advanced and under Items click on each item that allows Font changes and choose a larger Font. You can experiment with this until you get the desired effect. You can also adjust Icon size and spacing, etc. while you are at it.

    This technique worked wonders for me, now I have the size and screen fill of say a 1024x 768 resolution but with the clarity and sharpness of the monitor’s native resolution.

    Reply
  9. The dot pitch, not the size of the screen in pixels, is what determines how large a given pattern of pixels will appear (when displayed 1:1) on the screen.

    As Gabe pointed out, DPI should be a good solution to general scaling of the screen image, but can cause severe problems with programs that don’t handle it correctly. I normally run at ‘Large size (120 DPI)’, but occasionally have to switch to ‘Normal size (96 DPI)’ for this reason.

    The ‘Appearance’ settings mentioned by dkg1 work well for some text such as menus, but not for others such as ‘Message Box’, as most programs ignore this setting.

    Of course, the main text displayed by many programs such as browsers, Acrobat, and Word can be zoomed by settings within the program.

    Reply
  10. How do you tell if the “max res” is from the card(s) or the monitor on a laptop computer(with built-in screens)?

    I look up the specifications for all of them – online if need be at the manufacturer’s web site. (Though I typically check before I actually purchase.)

    Leo
    31-Mar-2010

    Reply
  11. @dkg1: The last time I tried it adjusting the Windows font size, I found that a lot of applications didn’t consider this in their testing/design. Thus, text was often truncated making some apps hard, annoying or impossible to use.

    Sadly this is extremely common, even after only minor changes. Having worked both sides of the issue, I can say that in particular for web pages it can be extremely difficult to do correctly.

    Leo
    31-Mar-2010

    Reply
  12. Hi Leo,
    Your articles are very helpfull in professional troubleshooting.. Looking forward for some tips on using Lotus Notes. I am new to this tool and have to understand it..
    Looking for your help.. And hope you have a very good Holidays..

    Reply
  13. My monitor is a 24-inch Samsung with a 1920×1200 recommended screen resolution. That setting will not fill out the whole monitor screen and makes the fonts too small to read. I adjusted the resolution to 1024×768, and under

    Reply

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