Going blind with 'high resolution' Video cards can make images smaller, not easier to read

Your computer

March 02, 1997|By Michael J. Himowitz

I GOT ELECTRONIC mail the other day from a fellow named Dan who installed a new video board in his computer and got a nasty surprise when he turned it on.

"I bought the video card because it was supposed to give me higher resolution, and I went through all the stuff I was supposed to and installed the programs from the disk that came with it," he said. "But when I started the computer back up, the picture wasn't any better. Everything was just a lot smaller. I could hardly make it out, even with my reading glasses. So I called up the help line and complained about it. They told me there was nothing wrong -- that's the way it was supposed to be. Am I just plain stupid, or did I get taken for a ride?"

Actually, Dan, you got exactly what you paid for.

The term "high resolution" is strictly relative when it comes to the image you see on the screen. But a lot of people spend money on computers with high-priced video cards and fancy monitors without realizing that they may not be getting what they really want -- a display that's easier to read.

Here's why.

The quality of the image on your monitor depends on three things: the video display circuitry in your computer, the capabilities of your monitor, and the software drivers that tell your computer how to draw the image. The term "resolution" actually refers to the number of little dots, or pixels, that your video board and monitor are capable of lighting up on the screen.

Now for some math. Most PCs typically operate at one of three resolutions, 640-by-480 pixels, 800-by-600 pixels, or 1024-by-768 pixels. At a resolution of 640-by-480, you monitor is displaying 480 rows of 640 dots each, for a total 307,200 dots.

Got it so far? Good, we're almost done. A typical 15-inch monitor has a display area that's about 11 inches across. So each of the 640 pixels takes up roughly 1/60th of an inch. That isn't very big.

Now here's the rub. When your PC displays a window, or an icon, or a character on the screen, it's usually displaying an image with a width and height that's defined in pixels. So a typical Windows program icon that's 32 pixels across will occupy about half an inch of real estate on the screen.

But let's use our Windows setup software to shift our computer to a higher resolution, say 800-by-600 pixels. Each pixel is now 1/80th of an inch wide, and the program icon is now less than 4/10 of an inch across.

And if we switch to really high resolution, the icon is only 3/10 of an inch wide. That's not easy to read from the typical monitor viewing distance of 18 to 24 inches, particularly in offices where glare from outside windows and fluorescent lights does its best to distract your eyes.

Things get worse when you spend a lot of time with text-intensive programs such as word processors or spreadsheets. The lines and curves that make up printed characters are typically only a few pixels wide to start with. When you start shrinking those pixels, you're asking your eyes to do a lot more work than they were made to do. But that's exactly FTC what happens each time you move to a higher resolution. The image quality hasn't improved one bit -- but your potential for eyestrain has.

So what's the advantage of a higher-resolution video board and monitor? Well, if you're in the graphics business, and your displaying photos in particular, you'll get a better view of larger images at higher resolutions.

And when each program's window is smaller, you can display more than one program on the screen at the same time. That's important to people who have to switch constantly between, say, a word processor and spreadsheet. If you're using a word processor or desktop publishing program, you'll see more of your document at once at higher resolution. With a spreadsheet, you can display more rows and columns.

Whether you can actually read what's displayed is a different question altogether. While a good video board and monitor will produce a sharp image with clearly-defined dots, there are limits to the detail your eyes can resolve. For that reason, most systems with 15-inch monitors are useless for text applications at resolutions higher than 800 by 600 pixels -- unless you have the eyes of a fighter pilot.

There is a solution to the problem of resolution vs. readability -- a larger screen. Because your monitor displays the same number of dots at any resolution -- regardless of the size of the screen -- each pixel on a larger monitor is slightly bigger and easier to see.

Possibly because there are so many middle-aged guys like me struggling with graphical interfaces, 17-inch monitors are becoming increasingly popular. They produce displays that are about 30 percent larger than 15-inch screens, which may not seem like a big difference. But it's enough to make your eyes a lot more comfortable at a resolution of 800-by-600 pixels and turn higher resolutions into workable alternatives for desktop publishing.

Seventeen-inch monitors typically cost about $300 more than their smaller cousins. Figure on $700 to $900 for a good one. Even larger monitors with 19- to 21-inch screens are available, but at $1,500 and up, they're too pricey for home use and they take up more desktop space than most users can spare.

While the price difference between a 15- and 17-inch monitor isn't exactly pocket change, your eyes are pretty valuable tools and you're only issued one pair. So they're worth protecting. If you're buying a new computer or you suffer from eyestrain now, check out a large-screen monitor. You'll like the big picture.

Pub Date: 3/02/97

Baltimore Sun Articles
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.