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Don't Fall for Monitor Sellers' 'Dot Pitch'

-- by Cynthia Morgan

If you based your last monitor purchase on dot pitch, you might just as well have considered shipping weight or the number of knobs at the bottom of the screen. Thanks to developments in display technology and cutthroat competition, the once cut-and-dried dot-pitch indicator has become a game of specmanship.

Dot pitch used to represent the distance between the centers of the two closest dots of the same color on a shadow mask. But when manufacturers began reporting dot pitch "equivalents" for new display technologies-where pixels' size, shape and even angles varied widely-the definition changed also.

"The problem is that, to users, dot pitch is the be-all and end-all measure of display quality-it's not, and it was never meant to be," said Rhoda Alexander, an analyst with Stanford Resources. "But because that's what's happened, dot pitch is not measured consistently, and it's easy to distort the numbers."

Off the record, many vendors concede the point. As one engineer, who asked not to be named, put it, "Dot pitch means pretty much whatever the company wants it to mean." For example, some now measure between outside edges, or at different depths within the monitor; others measure horizontally; still others define dot pitch as the average of horizontal and vertical measurements between pixels. The only thing these measurements have in common is that, to the customer, it sounds like the monitor in question has a finer resolution.

In fact, some don't even have a dot pitch. Aperture-grille monitors-these displays typically have "-tron" in their names, as in Trinitron and Diamondtron-display thin vertical stripes instead of small round dots. And none of the measurement methods take into account other key factors, such as pixel size and overall distribution, that also affect monitor resolution and quality.

So what should you do? Take a good, long look. "The buyer's personal visual comparison-how that monitor actually looks to the person who will be using it-is far more important" than phony numbers, Alexander advised. That's not completely reliable, of course, but it's probably as scientific as any other measure.

Windows Magazine, August 1997, page 64.

[ Go to August 1997 Table of Contents ]