CRT vs LCD: pixel aspect ratios

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andrew732

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Sep 1, 2009
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I recently replaced my CRT (Viewsonic G90fb) with my first LCD display (a HP LP2475w) and am very happy with the HP in general. Aside from the 3 or 4 stuck pixels, there’s only one small thing that’s nagging at me: items that should have identical aspect ratios on the old 4:3 Viewsonic and the new 16:10 HP do not. Everything looks slightly stretched in the vertical direction on the HP and I’m trying to figure out why.

For example, the “My Documents” icon on the Windows XP desktop is 69 pixels wide and 47 pixels high on the HP, for a theoretical aspect ratio of 1.468. Actually measuring it with a ruler, I got 1.461 for the aspect ratio, meaning (correct me if I’m wrong) that the HP’s pixels are perfectly square about as far as can be determined by hand. However, the same icon, measured in the same way, has an aspect ratio of 1.58, at both 800x600 and 1280x960 (4:3) resolutions on the Viewsonic. Why would this be the case? Is there some simple explanation, such as nonsquare pixels in the CRT? Are Viewsonics of that vintage known to have some particular pixel aspect ratio other than 1:1?
 
All LCDs have square pixels, and you can rest assured that as long as you run the HP at the 1920x1200 native resolution, over DVI, that you are seeing the image 100% as it should be.

CRTs don't have fixed pixels at all. You should be able to adjust the aspect ratio quite a bit by using the horizontal and vertical size controls. You could easily get this to 99% perfection by just drawing a perfect circle in Paint and measuring with a ruler, adjusting as necessary.
 
The HP LP2475w running on native resolution?... If not, you should at least run it at native ratio setting, which is 16:10...

and yes RMA it.
 
The geometry of your CRT is off. They are not a fixed pixel display. If you're worried about you LCD being off, just create a bitmap image in MSPaint that is 64x64 and fill it with a contrasting color. The measure it both way. You should get 1:1.
 
OK thanks, for years I've just been seeing the Windows desktop incorrectly then. :eek:

I guess I will RMA it if everyone thinks I shouldn't have to live with any stuck pixels. I thought 3 or 4 was something I should just accept seeing as how e.g., newegg's policy requires 8 for return. Luckily I bought from provantage.
 
ryan_975 said:
The geometry of your CRT is off. They are not a fixed pixel display. If you're worried about you LCD being off, just create a bitmap image in MSPaint that is 64x64 and fill it with a contrasting color. The measure it both way. You should get 1:1.
Click to expand...

I agree. Since you can adjust the horizontal and vertical sizing on a CRT quite easily, it was probably never quite right.
 
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