When the app is called Pixel Tester. Just from the name you already know what Pixel Tester does and whether or not you need to use it. Those of us who slave over a hot keyboard all day and stare into a gazillion multi-colored pixels know the irritation that comes from a dead pixel. Here’s how to find them.
Testing Pixels, Not For Fun
It should be noted right up front that after more than a dozen years of using Macs with LCD displays, I’ve only encounter dead pixels three times.
All three were incredibly irritating to view. One was on a new Mac screen so I returned it for a screen with live pixels.
The other two Mac screens, a few years ago, were actually massaged back to life by a trained technician. Think CPR for a dead pixel.
For the rest of us, here’s how to test for dead pixels using the Pixel Tester app.
The screen can be an Apple LCD display, or pretty much any other brand which has pixels. This is a good idea if you’re planning to buy a used LCD display.
Pixel Tester gives you a few options, including test colors (some are easier to see dead pixels than others) such as pure red, pure green, and pure blue (by using screen pointer motions). Or, black. Or white. A number of patterns are displayed to make it easier to detect a dead pixel, and the app works well on Macs with multiple screens attached.
Now, what can you do when you find a dead pixel? Not much. You may be able to return the screen to where you bought it and obtain a replacement. In some cases, when the screen’s glass is removed, a pixel can be massaged back to life.