LCD panel shadow effect caused by EMI from cables?

[moonbogg]

Have you heard of this? Having the data cable too close to the power cable or other sources of electromagnetic interference can cause disruptions in the signal, often leading to visual artifacts in the form of non uniform color reproduction and darkened shadow effects?

 

[corkyg]

Many of the effects of EMI border on witchcraft. If the cables are not properly shielded, such an effect could be possible. Does moving them apart have any real time effect on the display?

 

[moonbogg]

I moved the cables. Nothing happened, lol. Just thought I'd update you. I think my expectations were just too high for monitor uniformity on a non professional grade LCD panel.

 

[Alpha0mega]

What do you mean by "shadow effect"? Is it a shadow appearing on on-screen elements (gui etc.), even those that shouldn't have them? Like the mouse pointer showing a shadow, despite shadowing turned off? Or if you draw a straight line in an image program, it has a shadow?

If so, this isn't normal behavior, even for non-professional panels, nor should this be caused by any EM interference IMO (especially for a digital connection, which I presume you are using). It's a faulty monitor. I have had multiple monitors that eventually developed this problem. Two Samsung TN panels, and one Dell WFP2407 (PVA). In all cases the monitors were fine for years, and later developed the shadows on all on-screen items overnight. The Samsung service center replaced the monitor interiors (LCD+PCB), which fixed the problem. Dell replaced the whole thing.

Just speculation, but I think it's a fault in the image processing hardware. The panel or cable itself doesn't have the "brains" to selectively modify the image. Non-uniform color is just the panel though. Even the best panels don't have perfectly uniform color, at least I have never seen a perfect one. Cheaper ones have it worse, of course.

 

[moonbogg]

Its just a darker area of the monitor. Non uniform white/gray levels for instance.

 

[Alpha0mega]

Oh, that's just poor panel quality. The best professional monitors are much better in this regard, but still not perfect. Most other panels are much worse in comparison.

 

[moonbogg]

Oh, that's just poor panel quality. The best professional monitors are much better in this regard, but still not perfect. Most other panels are much worse in comparison.

So is it poor panel quality, or standard panel quality? I thought my "issue" was unique, but the more I research, the more I get the feeling that this is pretty common, which is sad. Sounds like in order to get a good uniform panel you need to spend a few grand.

 

[Cerb]

These monitors are being fed DP, HDMI, or DVI, correct?

 

[Alpha0mega]

So is it poor panel quality, or standard panel quality? I thought my "issue" was unique, but the more I research, the more I get the feeling that this is pretty common, which is sad. Sounds like in order to get a good uniform panel you need to spend a few grand.

I can see how my wording was ambiguous. I meant that lower cost panels usually display poorer brightness and color consistency, compared to higher quality/cost panels. I can't say if yours is exceptionally bad or not without looking at it, but it's probably same as most normal panels. Try getting a look at another similar monitor if you can.

You needn't spend "a few grand", unless you are going really big and high-end. Depending the panel size and quality, you get good monitors <USD 1000. I have found Dell Ultrasharps to be quite good. Also remember, in the end, panel uniformity etc. are crap-shoots. No two panels will be the same, even in the same line.

 

[moonbogg]

I can see how my wording was ambiguous. I meant that lower cost panels usually display poorer brightness and color consistency, compared to higher quality/cost panels. I can't say if yours is exceptionally bad or not without looking at it, but it's probably same as most normal panels. Try getting a look at another similar monitor if you can.

You needn't spend "a few grand", unless you are going really big and high-end. Depending the panel size and quality, you get good monitors <USD 1000. I have found Dell Ultrasharps to be quite good. Also remember, in the end, panel uniformity etc. are crap-shoots. No two panels will be the same, even in the same line.

Yeah, I just think its silly how people get all excited about IPS monitors for their color accuracy when many of them (most probably) can't even display a single color correctly across the screen. It really defeats the purpose of good color reproduction when uniformity is not solid. The main benefit to this IPS panel and many others likely is viewing angles, that's it.
If you look at a solid gray screen and half of it looks different from the other half, then that panel fails to display even a single color let alone over 16 million.

 

[Alpha0mega]

Good IPS panels do have vastly better color accuracy and consistency, even if it's not perfect. Better/worse is a measure inherently relative to available alternatives. Modern high-end IPS panels (not E-IPS), though not perfect, make other panel types look like a joke. It's a difference of not seeing the gradient shift until you really look for it vs. the color difference not being ignorable. Or the difference between bitten by a dog vs. a lion. I would rather not be bitten at all, but if I had to choose... 😛

The best panel I have ever seen is the one I am currently using, the Dell U2713H. It's AH-IPS panel is truly breathtakingly beautiful, let down by the insane overdrive that Dell foisted on it. In context of the current discussion, it's the only panel that doesn't have any discernible color shift, either from left-to-right or top-to-bottom that I can see with my naked eyes.

However, I am with you about the state of current monitors not being satisfactory. We shouldn't have to compromise on such basics. Display tech just isn't moving fast enough. Maybe OLED will be better, but that's perpetually far away from becoming mainstream.

 

[moonbogg]

Good IPS panels do have vastly better color accuracy and consistency, even if it's not perfect. Better/worse is a measure inherently relative to available alternatives. Modern high-end IPS panels (not E-IPS), though not perfect, make other panel types look like a joke. It's a difference of not seeing the gradient shift until you really look for it vs. the color difference not being ignorable. Or the difference between bitten by a dog vs. a lion. I would rather not be bitten at all, but if I had to choose... 😛

The best panel I have ever seen is the one I am currently using, the Dell U2713H. It's AH-IPS panel is truly breathtakingly beautiful, let down by the insane overdrive that Dell foisted on it. In context of the current discussion, it's the only panel that doesn't have any discernible color shift, either from left-to-right or top-to-bottom that I can see with my naked eyes.

However, I am with you about the state of current monitors not being satisfactory. We shouldn't have to compromise on such basics. Display tech just isn't moving fast enough. Maybe OLED will be better, but that's perpetually far away from becoming mainstream.

I'm glad to head your Dell is nice. I've heard good things about them. The panel I am using and talking about here is the new Acer XB270HU. Its the fast gaming AHVA panel. The lack of white and soft color uniformity drives me up the wall insane. During a movie or game with a constantly changing dynamic image, its hard to spot for sure, but browsing the web or something, its there and it makes me want to either smash the panel or rip my eyes out.

 

[corkyg]

I have two Dell 24-in IPS monitors, and they are very uniform across the screen.I have no experience with Acer.