Buyer's Guide: Monitors

Your monitor is your window into what your computer is doing, as well as what is happening beyond your desktop in cyberspace. Buying a monitor that makes looking out that window a productive experience is something you want to consider carefully. Here's some guidance to take into account before you get your next desktop display.

What do you want to pay for your next display? Monitor prices range from under $200 to $1,200 or more. Typically, pricing is pegged to size; the bigger the monitor (measured diagonally), the bigger the price. That's a very rough rule of thumb, though. Other factors such as contrast ratio, high definition support, available inputs, backlighting technology and built-in intelligence -- just to name a few -- will affect the price tag, too.

When buying a new flat-panel monitor, you should have a broad familiarity with the technology behind it. The most common active-matrix technologies used in TFT (thin-film transistor) liquid crystal displays are twisted nematic (TN) and in-plane switching (IPS).

NEC AccuSync AS231WM

TN displays use liquid crystal elements that twist or untwist to allow light to pass through them. They use single transistors to control the voltages to the liquid crystal cells. The amount of voltage applied to the cells determines their degree of twist and the properties of the light passing through them.

IPS displays, which cost more to produce than TN panels, orient their liquid crystals horizontally. Two transistors are used to manipulate light passing through the crystal. The result is that IPS monitors usually have better contrast, brightness and color definition at wider viewing angles than TN displays.

Everyone Has an Angle

A monitor's viewing angle can be important for a number of reasons. As the size of a monitor increases, an increased viewing angle will make the edges of the screen appear as clear as its center. What's more, you don't want colors and sharpness changing on you every time you move your head or change your position in your chair.

In addition, if you're using more than one monitor at a time, chances are you'll be eyeing your monitors at angles greater than dead center, so a broad viewing angle will be a necessity. And if you ever work with colleagues at your desk, a wide viewing angle is needed for everyone to see what's on screen.

Viewing angle specs usually have a horizontal and vertical component -- an advertised 160/170, for example, means a horizontal angle of 160 and a vertical angle of 170 degrees. In today's market, a viewing angle of 160/160 is considered good, 170/170 better and 178/178 best. Since IPS monitors have inherently wide viewing angles, ratings from their makers are usually accurate, but the ratings accompanying TN monitors can be inflated. That's why, if possible, it's a good idea to research the accuracy of viewing angle claims before buying a TN screen.

Monitors come not only in different sizes but different shapes -- some more squarish, others more rectangular. A screen's aspect ratio, the relationship between its width and height, is determined by its native resolution: A display with a resolution of 1,600 by 1,200 pixels has an aspect ratio of 4:3, a 1,280 by 1,024 screen a ratio of 5:4 -- and both are increasingly being displaced by widescreen aspect ratios of 16:10 or the 16:9 of high-definition TV and video (1080p HD has a resolution of 1,920 by 1,080).

If you're buying a smaller monitor -- 20 inches or less -- and will be using it for general computing chores rather than watching movies, the squarer ratios may be more comfortable to work with because the reduction in vertical space won't seem as severe. On larger screens -- 22 inches and above -- the dearth of vertical space is less bothersome.

Samsung P2370-1

It's possible to look at two monitors of the same size with the same resolution and have the image on one appear smaller than the other. That's because the distance between the pixels on screen, called pixel pitch, is smaller on one than the other. A smaller pixel pitch makes graphics appear sharper, but also makes text (at the same font size) look smaller. So, for example, while the Samsung 2333SW ($210) and Dell Professional P2310 ($260) are both 23-inch displays with 1,920 by 1,080 resolution, type on the Dell unit, which has a pitch of 0.27 millimeters, will appear smaller than on the Samsung, which has a pitch of 0.28mm.

Watch Your Back(lighting)

Most flat-panel monitors use cold-cathode fluorescent lamps (CCFLs) to illuminate their pixels. Light from the CCFL is diffused evenly across the display by a panel behind the LCD. This method produces results adequate for most computing purposes. It does, however, lack precision. For finer control of a monitor's backlighting, desktop and notebook display manufacturers are increasingly turning to light-emitting diode (LED) technology.

With LEDs, light to the pixels can be controlled more effectively; not only can the light to specific areas be better modulated, it can be turned off entirely. That means darker blacks and higher contrast ratios (the span from the darkest to lightest colors that a monitor can produce; more on that in a minute).

Backlighting also affects a display's color gamut -- the number of colors that can be shown on a monitor. When evaluating LCD monitors, the benchmark used is NTSC, a standard used for broadcast television. A typical LCD with CCFL backlighting, for example, will be able to show about 75 percent of the NTSC gamut. A wide-gamut CCFL will provide 100 percent of NTSC. And there are wide-gamut LED monitors that can produce a color palette beyond 100 percent of NTSC.

Along with color gamut, monitor makers like to talk about color depth. Color depth defines the number of levels that each primary color can render. The standard is what's referred to as 24-bit color -- 8 bits or 256 levels apiece for red, green, and blue, which adds up to 16.7 million color combinations. Some high-end monitor manufacturers pair 24-bit panels with a 10- or 12-bit color lookup table to get more than 16.7 million choices for their 16.7 million slots. HP's DreamColor LP2480zx Professional Display ($1,999) uses 30-bit LCD technology to permit over a billion active colors.

When choosing a monitor, you'll want one that has a color gamut and depth that suits your needs. If text and PowerPoint presentations are your primary concerns, a gigantic color palette won't be necessary. If top-quality imaging, video editing, or prepress work will occupy your time, then you'll want to up the ante for what you look for in a monitor.