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††††††††††††††††††††††††††††††††††††† ††BY: GURU (DAVE SMITH )


If you're going to stare at something for eight or nine hours a day, it had better look good. Here'swhat you need to know when choosing your next monitor.


Q: When buying a new monitor, do you guys think dot pitch or viewable area is more important?


Refresh rate, viewable area and dot pitch are the most important factors to consider when shopping for a monitor.

Essentially, you want the best measure of these threemetrics. Something like a 21-inch monitor with a .22mm dot pitch that can refresh itself at a the rate of 100Hz would be ideal.


If you must choose between viewable area and dot pitch, your eyes will be happier with a 17-inch monitorwith a sub-.25mm dot pitch than with a 21-inchmonitor with an unacceptable .30mm to .40mm dot pitch.


Confused? Below you'll find explanations of what Imean by refresh rate, dot pitch, viewable area and

††††††††††††††other metrics. Study up before buying your next monitor. Just remember, even if you equip yourself

††††††††††††††† with enough monitor nomenclature to make an educated online purchase, you really ought to stop by

††††††††††††††† the computer store and kick the tires of some side-by-side floor models before making your final decision.

Viewable Area

Viewable area is how big the screen is. Not a difficult concept to grasp. Unfortunately, in the past monitor

manufacturers have been shifty about the way they measure viewable area. Just because you have a 21-inch monitor doesn't mean the viewable area is 21-inches. Manufacturers derive viewable area numbers bymeasuring diagonally, not horizontally, as tech neophytes and A/V club dropouts would naturally assume. The viewable area published by monitor manufacturers describes the size of the monitor's cathode ray tube (CRT), not the size of the screen. This is pretty lame because a monitor's plastic casing typically blocks about an inch of CRT.


Most monitor boxes now list both the CRT sizeand the viewable area. You want to make sure to get a 17-inch monitor with 16 inches ofviewable space. A 19-inch monitor typically offers 18 inches of screen space. A 21-inch monitor offers 19 to 20 inches.


Not everyone needs a 21-incher. But if you work in engineering, desktop publishing, graphic design or any other profession where you have a lot of content onscreen at once, you owe yourself as much viewable area as you can afford. What's more, a large monitor permits you to view content at sharp, high resolutionswithout that content getting too tiny -- a majorproblem with small monitors set at high resolutions.


Dot Pitch (and Stripe Pitch)

The image on most CRT monitors is composed ofmillions of tiny, colored phosphor dots. When the electron guns firing from the back of the tube strike these dots, they emit color, and, in a wondrous act of mass cooperation, form a display image.

The closer the dots are to one another the sharper theimage. Dot pitch is the metric used to describe thedensity of the dots. Specifically, dot pitch is the distance between two like-colored phosphor dots (they're arranged in groups of three; one red, one blue, one green). Shoot for a dot pitch of .25mm or below and don't consider a monitor with a dot pitch

above .28mm.


Shadow MasksBecause the electron gun moves so rapidly, a filter isused to train the beam onto the appropriate dots.

Shadow masks -- thin sheets of metal perforated bypinholes -- are the most commonly used and leastexpensive filters. If you buy a shadow-maskedmonitor, make sure it's an INVAR shadow mask. Thistype employs a special metal that resists heat overtime and prevents the mask from warping, aphenomenon that distorts the mask's ability to train the electron beam onto the appropriate phosphor dots.




Refresh Rate

Without a fast refresh rate your monitor will flicker. Flicker makes your eyes water and your head throb. There are vertical and horizontal refresh rates, but when you hear about refresh rates in a Silicon Valley bar, or when you see a number quoted in a monitor's spec sheet, you're talking vertical refresh rate.


Vertical refresh rate is a measure of how many times per second the screen gets redrawn from top to bottom. Measured in hertz, a monitor with a vertical refresh rate of 75 Hz (the VESA standard) gets redrawn 75 times per second.


Most people can't perceive any flicker on monitors with refresh rates in excess of 72 Hz, but some peoplerequire rates as high as 85 Hz to avoid discomfort. High refresh rate is especially important on big monitors running at high resolutions because there aremore lines to be refreshed. Pat Norton usually maxesthe refresh rate on the monitor he's using. (His eyesare getting old, you know.)


Note: You'll need a graphics card to get those really spiffy, high refresh rates.

There's also horizontal refresh rate, which is a measure of how many horizontal lines can be displayed per second. A high horizontal refresh rate permits high resolutions, but it's not a metric youreally need to worry about when shopping for yournext monitor.


Flat Screen CRT†† DONíT be confused by a Flat Pannel ScreenFlat Screen CRT is the best to buy for most users Manymanufactures, use flat tubes. Actually, the tube/screen is slightly curved, but so gently you really can't tell. The flat tube and screen keep the pictureundistorted across the entire screen -- even in thecorners. With conventional picture tubes, images in the corners of the screen can get magnified because of the screen'sconvexity. Moreover, flat tube CRTs use alens system that adjusts the focal distance inaccordance with the beam trajectory, bringing all partsof the screen into focus.