lent's Journal: Testing LCDS

Stolen shamelessly from Buying an LCD? Buying an LCD? (Score:5, Insightful)
by Boss, Pointy Haired (537010) on Thursday
April 10, @11:20PM (#5707671)
Explain to the sales droid that LCD displays can have dead [or permanently alive] pixels. It probably won't know that knackered pixels are expected, but the vast majority of displays are perfect, so there's no harm in making sure you get a perfect one.

Unpack the display and plug it into a PC in the store. Now you need to check both a completely white screen and a completely black screen - because knackered pixels can be knackered either always on or always off.

To check always off, fire up Internet Explorer, go to "about:blank" (try it)and press F11 (full screen). This will give you a page full of white. Scan the page closely looking for "always off" dead pixels.

Then, to test for always on pixels, right click on the desktop and go to screen saver. Select "Blank" and then "Preview". Again, scan the blank screen and this time look for "always on" pixels - although these are much easier to spot!

Re:Buying an LCD? by BJH (Score:2) Thursday April 10, @11:29PM
Re:Buying an LCD? (Score:4, Informative)
by 200_success (623160) on Thursday April 10, @11:44PM (#5707827)
So, first go to about:blank, then to javscript:void(document.bgColor='red'), javscript:void(document.bgColor='green'), and javscript:void(document.bgColor='blue') with Full Screen (F11) after each color. April 10, @11:57PM technically... (Score:4, Informative)
by rebelcool (247749) on Thursday April 10, @11:59PM (#5707918)
it should be the other way around. An LCD 'turns on' its pixel so it becomes opaque - that is, black.

A pixel is 'turned off' (goes clear) and lets the white backlight through it to display white.

This is why LCD's are not as good at displaying black as CRT's. The backlight is always on, and the pixels can have varying degrees of opaqueness when turned on. This makes black more of an uneven very dark gray (well, uneven on my LCD anyway..newer ones might be better at it)

Also, they won't necessarily be black or white. I have some green dead pixels.