Intro:
Before you begin

Part 1:
Learn about
image quality

Step 1:
Understand image sharpness
Step 2:
Understand image brightness
Step 3:
Understand image consistency
Step 4:
Understand image contrast
Step 5:
Understand color purity
Step 6:
Understand screen resolution
Step 7:
Understand screen refresh rates
Step 8:
Understand screen flatness

Part 2:
Explore image
adjustment options

Step 1:
Center the image onscreen
Step 2:
Make necessary adjustments

Part 3:
Decide on a monitor size

2torial #0678:
Learn2 Shop For a Computer Monitor

You've only got one set of eyes...

O.K. folks, let's be open about this: your computer monitor can be the most personally-detrimental part of your whole computer system. No other component has such potential to damage you (unless you've got the nervous habit of chewing on power cables). That bright, happy, box can give you headaches, cause severe eyestrain, and bombard you with various forms of radiation.

That's why you need to consider your next monitor about as carefully as you'd consider your next sweetheart. Your monitor is like your sweetheart: it can be a bit temperamental, it's with you much of the day, and it may have a greater effect on your life than you'd expect.

There are two basic types of monitors widely available on the market today; the Trinitron (or aperture grille), and the shadow mask (see Keywords). The best shadow masks are called InVar masks and use a special alloy which resists distortion much better than traditional shadow masks. Terrific monitors can be produced using either technology, but inferior monitors can be produced as well, so you should shop with care.

When you buy a monitor, you have three major concerns:

• The sharpness (focus) of the image,
  
  
• The brightness of image
  
  
• The consistency of the image as it spreads from the center of the screen to the edge.

A good monitor will have more contrast, and purer colors than an inferior one, and will maintain those qualities for a longer time. The screen should be fairly flat as well, to minimize image distortion. It'll also meet or exceed the standards for radiation emission and energy usage developed in countries such as Sweden and the United States.

Many monitors allow you to adjust the onscreen image to suit the current computer user. These adjustments can be accomplished through the use of digital controls, which most often involve pushbuttons and onscreen menus; or alternatively, more traditional dials and switches. These adjustment controls are highly desirable features: it's a good idea to familiarize yourself with their function and understand their ability to improve the onscreen image.

Part 1: Learn about image quality

Image quality is really a catch-all term for the concerns listed below. It's affected by all kinds of factors that you never think about under normal circumstances; power supplies, circuit boards, capacitors and filters to name a few. Better-quality monitors use higher-grade parts which perform better and last longer. Not surprisingly, the use of higher quality parts is often reflected in the price of the monitor.

Understand image sharpness

The smaller the dot pitch, the better. Picture sharpness is largely the result of the dot pitch of the picture tube, and in this instance a smaller number is better. Right now, the best monitors have dot pitches of .22 millimeters, while the worst can measure .36 millimeters or greater. Generally speaking, a 15" monitor should have a dot pitch of .28mm or less, while 17" and 20" monitors should have a dot pitch of .30mm or less. While dot pitch is not the only thing that affects picture focus, it's a good indicator of how sharp the image will be.

Understand image brightness

When you buy a monitor, it should be capable of producing as bright a picture as possible when it's new. As any monitor ages, it loses some of its brightness, so you want to start with as much brightness as possible. Unfortunately, manufacturers don't usually provide a quantified figure with which you can compare models, so you're pretty much left to your own judgment. One thing to look for is a monitor that's bright at the edges as well as in the center of the screen. And if you're comparing monitors side by side, make sure their brightness controls are roughly the same; if one monitor is set radically different than the other one, you can't make a fair comparison.

Understand image consistency

Lines and shapes should not be wavy. To begin with, you should realize that no monitor can produce an image at the outer edges of the screen as clearly as it can at the center. You're looking for a monitor that consistently represents the image from edge to edge with as little distortion as possible. For instance, a horizontal line onscreen should not bend or waver from left to right, and a vertical line shouldn't bulge in the middle and at its ends. Additionally, as a monitor screen heats up from extended use, a poorly designed monitor will develop small, discolored or darkened areas on the screen. As a result, it's a good idea to let a monitor be switched on for a while, and then check for image consistency.

Understand image contrast

A better monitor produces darker blacks and lighter whites than another monitor of lower quality. This is one reason why manufacturers use very darkly tinted screens these days. When comparing monitors, again make sure that each has its adjustment set similarly, and then look at the black areas onscreen. If the monitors have an adjustable color temperature control, make sure that they're at the same setting. Otherwise you're not making a fair comparison: one might look worse simply because its settings aren't optimal.

Understand color purity

• Primary colors should stay primary. The image that you see onscreen is actually made up of three colors: red, green and blue. A poorly designed or defective monitor will let these colors bleed into another. For example, white areas on the screen may develop a noticeable tint from a nearby colored image. A rainbow effect, or moire pattern, may become visible under some circumstances.
  
• Color impurities can also arise when a monitor needs to be degaussed. If the store will allow the monitor to be turned off for an hour (and you have the time to spend) do so and return after the hour. Most monitors will degauss when allowed to cool down completely. You may then determine if the impurity is still noticeable.

Understand screen resolution

Resolution relates to dots per inch. Your screen images are formed by a grid of thousands of tiny dots, called pixels. The higher amount of dots per inch (DPI or PPI--pixels per inch), the sharper the resolution. Most monitors you can buy nowadays are multi-scan models: they can easily switch from one resolution to another. The standard monitor resolution is 72 DPI.

Consider what you'll be using the computer for before you commit to a high DPI. For instance, if you'll be working with image processing applications (such as Photoshop) you'll probably want a high-resolution image. On the other hand, if you'll mainly be using the computer for word processing, standard or even low-resolution should be fine.

Understand screen refresh rates

Note your refresh rate. The image that you see onscreen doesn't appear onscreen continuously--it flashes on and off. And it flashes quickly enough to appear as if it's always there. The speed of the flashing is called the refresh rate, and this is an important figure to remember. A monitor with a refresh rate that's too low will appear to flicker somewhat, which can result in headaches and eyestrain. Higher resolutions demand higher refresh rates, and a better monitor will have an advertised refresh rate of at least 70Hz for most resolutions. Remember, higher numbers are better when comparing refresh rates.

Understand screen flatness

Screen flatness is generally considered a desirable feature. This is mostly due to the fact that a flatter screen will have fewer annoying reflections from the room you're in. A flatter screen also reduces image distortion that occurs at the screen edge, and has a slightly wider field of view than other screens. No screen is completely flat, but a better monitor will have a noticeably flatter screen than a cheapie.

Part 2: Explore image adjustment options

As previously mentioned, many of the newest monitors provide some control over onscreen image appearance. These serve quite a few purposes; the most important is the ability to compensate, to some degree, for the ageing of the monitor and a deterioration in performance. Digital controls with onscreen menus are preferable to manual dials and switches--there are no moving parts to wear out, break, or become dirty. Remember, the more controls for image adjustment that your monitor has, the better.

Center the image onscreen

Watch for off-centered images. Sometimes the image may become off-center--there may be more black area on one side of the image than on the opposite side. (This is can happen if the screen resolution is changed.) There's generally an adjustment for this in both digital and traditional, manual controls.

Make necessary adjustments

Contrast and brightness deteriorate over the years, so it's important that these controls operate well. Again, both digital and traditional controls usually provide for these adjustments, allowing you to improve the quality of the image as the monitor components wear out.

• Adjust image size
  You know that black area that surrounds what you can see onscreen? Well, now you can expand the onscreen image so that there's less black area, and in some cases none at all. There's a trade-off, though: the image quality at the edge of the screen can be poorer than elsewhere onscreen (see above), and in some cases, the overall image quality may suffer. This adjustment is usually only possible with digital controls.
  
• Adjust image shape
  Ideally, the image onscreen should be a perfect rectangle. Image-shape adjustments allow you to compensate if the sides of the image slant in one direction, or if the image bulges in the middle, or bows at the ends (and looks a bit like an hourglass). The amount of adjustment that's possible for these problems varies widely from one monitor to the next, and it's yet another adjustment that's only available with digital controls.
  

• Adjust image rotation
  Sometimes, the onscreen image is misaligned within the plastic casing of the monitor. It looks tilted towards one direction or another, and it can be most annoying for some. The ability to rotate the image onscreen is quite useful, but is only available with digital controls.
  
• Adjust color temperature controls
  Color temperature regulation aids your graphics. If you've ever seen how many kinds of white paint are sold in a paint store, you have an idea what color temperature is. Graphics professionals want the ability to make the image onscreen have slightly different color values at different times. This adjustment is generally only available on high-end monitors with digital controls. If your monitor doesn't provide this feature, you may sometimes gain it through use of a good video card.

Part 3: Decide on a monitor size

• The largest may not always be the best. Monitors are generally available in 14", 15" and 17" sizes, as well as the really big 20" and 21" ones. While most people tend to buy the largest monitor they can afford, be careful--your computer in its current configuration may not support anything larger than 15."
  
  
• Beware of space and hardware limitations. Larger monitors require a more powerful video card to run them. If your owner's manual tells you that you can use up to a 15" monitor, you'll need to buy and install a new video card to support anything larger. In general, a 17" monitor is large enough for most uses, but graphics and multimedia professionals often use larger ones.

So there you have it. There's a lot more to a monitor than meets the eye, eh? Well, bad puns aside, keep this in mind-- buy the best (not the biggest or the most gimmicky) monitor you can afford. You're gonna be looking at this thing for a long time, and the better the image quality, the less headaches and eyestrain you'll have. It's a worthwhile investment.