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How many pixels are too many? The unspoken drawbacks of higher resolution

Google-Chromebook-Pixel-thumb

Display resolutions have surged upwards over the last several years. Smartphones, tablets, and laptops are part of this trend, and the results have been dramatic. Today, users can buy 13-inch laptops with more pixels than they could find on 30-inch monitors, and 5-inch smartphones that offer the same resolution as 55-inch HDTVs. Google has even introduced a high-resolution Chromebook called the Pixel.

This pixel war is based on a simple premise: More is better. But does this supposed truism hold up, or can more pixels cause more headaches than they’re worth?

Recreating reality

Let’s start with a question. Why are more pixels desirable?

The answer is sharpness. Our view of reality is not made up of pixels, but LED displays are. They use the pixels available to create a representation that’s as close as possible to reality. Each pixel is adjusted so that the correct image is created. More pixels allow for more detail and a sharper, more realistic rendering of the content shown.

There is more to a realistic image than sharpness, of course. A cheap 1080p monitor can’t match up to the image quality of a $3,000 high-end HDTV with local LED backlighting. But, sharpness acts as a baseline. Once you become conscious of the pixels on a display, your suspension of disbelief will be broken no matter the display’s other traits.

Media isn’t the only arena where sharpness matters. Productivity also benefits. High resolutions can make text easier to read, render images more accurately, and display Web pages at different sizes without loss of detail.

The scales of sharpness

So far, increasing resolution seems like a win-win. More pixels means more detail and a larger virtual workspace. Why complain?

Unfortunately, the issue isn’t that simple for displays tied to a computer, tablet, or smartphone. Software developed for these devices are always coded with a certain resolution in mind. A Windows application, for example, might create a window that’s 640 x 480. A window this size would take up a moderate portion of a 1366 x 768 laptop display.

Most consumers will be happier with more pixels than less, but there are times when a high resolution means more trouble.

View that same window on a 1080p monitor, however, and it looks too small. If the monitor itself is small in size (as with a 13-inch Ultrabook, for example), the window’s contents could be difficult to make out.

Windows, and other operating systems, compensate for this by scaling up content that might be too small. But contrary to what CSI suggests, an image doesn’t become more detailed when its size is increased. What a scaling algorithm really does is use math to guess what the new pixels should look like and then fill them in. Results vary depending on an algorithm’s quality, but blurriness is usually introduced, which is precisely the opposite of what consumers expect when they purchase a high-resolution display.

Microsoft’s operating system isn’t alone in struggling with this problem. Every option sold, from OS X to Android, deals with it. Open an older Android game on your next Nexus 10 tablet, for example, and you may find a blurry mess of plus-sized pixels.

These tired eyes

Increasing resolution can cause displays to run afoul of another issue – our own eyes.

Let’s return to the example of a 640 x 480 window. As mentioned, if this window isn’t scaled, it may appear too small to read on a small 1080p display. Why? Because the reduction of the display’s physical size also reduces the physical size of everything it renders.

Let’s compare two monitors. The first is a 24-inch 1080p display. Based on the size and the pixel count, this monitor displays about 91 pixels per inch, which works out to a 640 x 480 window that’s 7 inches wide. That’s large enough for most people to read without difficulty.

Now, replace the 24-inch with a 13-inch display like that found on high-end Ultrabooks. The pixels-per-inch shoots up to about 170, which means the 640 x 480 window is now a bit less than 4-inches wide – and everything shown inside it has shrunk by a similar amount. It’s now much more difficult to read unless scaled to appear larger. And Windows 8’s scaling is unreliable.   

Technology journalists, who tend to be young, often wonder why so many people buy large laptops with pitiful 1366 x 768 displays. This example is the answer. As resolutions go up, and displays become smaller, everything shown on them becomes smaller and more difficult to read unless it’s scaled. People with poor sight are often more comfortable with a low display resolution because everything shown on it appears larger – and thus easier to read.

The importance of this issue depends on the quality of scaling a system can provide. Apple’s iPhone and iPad offer excellent scaling that makes this problem almost a non-issue. Windows 8 laptops, however, still have trouble with scaling content – so people with poor eyesight might want to stick with a 1366 x 768 or a 1600 x 900 panel. We’ve also run across Android apps that were obviously not coded with high-resolution displays in mind.

Performance and pixels

One final concern that stems from pixel proliferation is performance. Every pixel must be rendered, so more pixels equal more work for the graphics chip. This is why most current-gen console games don’t render at 1080p but instead stick to 720p, and up-scale the resulting image.

The difference isn’t negligible. A 1080p display has roughly twice the pixels of a 720p display, so rendering an image is roughly twice as difficult. HTC’s new Droid DNA smartphone is an example of the consequences. Though powered by an extremely quick quad-core processor, we noticed some performance hiccups while conducting our review. These issues occur because the Droid DNA packs a 1080p display in its 5-inch body.

Though different devices have different capabilities, the problem doesn’t go away. Of course, a high-end gaming laptop with 1080p resolution isn’t going to suffer interface lag – but it could have difficultly playing 3D games that a competitor with a lower resolution can handle.

Most gamers want a 1080p panel with high-end hardware and will simply spend more to get the best of both worlds. But what if you have to game on an inexpensive system? If that’s your intention, a display with fewer pixels could be the better choice.  

More pixels are better, but…

These points may make a high-resolution display seem like a bad idea. That’s not what we’re getting at. Most consumers will be happier with more pixels than less. Also, panels with a high resolution tend to be of better quality in other areas as well. Your money usually buys increased color accuracy and better viewing angles along with more pixels.

But too many pixels is a thing. If you have poor eyesight, if you wish to game without spending much money, or if you use a lot of legacy applications, pushing more pixels could actually detract from your experience.

More is better, except when it’s not.  

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