IPS image persistence and being an idiot.

Colstan

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As many of you may be aware, various types of screen technology can experience a form of "ghosting", where a static image continues to persist on the screen even after the image is no longer being displayed. In the olden days, a monochromatic amber or green CRT monitor could experience this when the phosphor compounds which emit light to produce images lose their luminance with use. Sometimes, these images were visible when the monitor was powered off. This is called "burn in", and in most cases, could not be fixed.

Screen_burn_screen_off.png


In modern times, this has become less of a problem, but is still a significant issue for most screen technologies. Plasma televisions, produced until 2007, were highly susceptible to burn in.

Plasma_burn-in_at_DFW_airport.jpg


Even modern LCD panels can suffer from image persistance, but this isn't always permanent. Here's an LCD television which has the CNN logo haunting the corner:

Emerson-McDonalds_CNN_Burn-In.jpg


More recently, OLED panels have shipped in many high-end televisions, and are now making their way into the high-end computer monitor category. The 27-inch LG UltraGear gaming monitor is the firs entrant in this area, which does not feature a widescreen aspect ratio.

OLED displays are at a significant risk of permanent burn in, they lose their brightness over time, relative to the pixels next to it, because they are self-illuminated. Manufacturers have implemented many mitigation techniques, such as screen shifting, pixel refreshing, and auto adjustment of logo luminance. End users can also mitigate the issue by setting a screen saver to a short interval and sleeping the display whenever it is not in use.

Once burn in is experienced in an OLED, it is unlikely to go away. The CNN poltergeist also haunts OLEDs:

OLED-Burn-In-Issues-0620.jpg


However, when it comes to computer monitors, the most common type used today are based upon IPS LCD panels. It's more unusual for these monitors to experience permanent burn in, and instead experience image retention. Image retention however can be permanent when the liquid crystals are unable to twist fully in either direction.

If you see static elements retained in your IPS monitor, you can try an image retention clearing pattern and display it for as long as necessary, until the static elements go away, or it simply doesn't work. Regardless, chances are better than not that this will resolve the issue. Apple has an alternate solution, which has worked for me in the past, and that is to set a white background while using the screensaver for an extended period of time. Regardless of method used, it doesn't always work and you could have CNN haunting your monitor for all eternity.

I personally experienced this as a chronic problem with my old Dell monitor, a 2005FPW that used the same panel as the 20-inch Apple Cinema Display, except it was considerably cheaper, when released in 2005. I used that same monitor for a total of 16 years, until Apple stopped supporting sub-pixel anti-aliasing in macOS, with them now pushing "Retina" class monitors featuring a much higher pixel density.

This Dell would regularly have static elements, such as the Dock, clearly persistent when displayed on any white or grey background. To fix it I would do as Apple suggests and display an all white image overnight, perhaps for a few nights, which would completely eliminate the image persistence.

Once Apple switched to "Retina" class monitors, I needed to find an alternative, as I could only stay on macOS Mojave for so long. Any version of macOS after that would give me physical headaches from the blurry image of a standard definition monitor that would be produced while using macOS. Hence, I finally needed to retire my old Dell.

The difficulty with finding a "Retina" class monitor is that Apple's specifications require a PPI (pixels per inch) display with a value of around 219ppi. Monitors of this density are rare, and are mostly available from Apple, LG, and an upcoming model from Samsung. If you've ever shopped for one of these monitors, they cost substantially north of $1,000 USD, just as a starting point, excluding used units of questionable provenance. The exception was the 21.5-inch 4K LG UltraFine which had been released alongside the 5K 27-inch back in 2016. The 21.5-inch 4K was canceled in 2019, whereas its 5K big brother is still being manufactured.

The smaller version originally had a suggested price of around $700 USD. Back in the Summer of 2021, I somehow managed to find a brand new, unopened model on Ebay for $342. Checking the EDID file, it had a manufacturing date of the 5th week of 2017. Where this technological leprechaun had been hiding for over four years, I'm not sure, but I verified that it was unopened when I first got it.

This is the same monitor that I am using right now. I've been babying it, because the Apple Studio Display isn't just expensive, but offers nothing more than I already have with this LG. Sure, it's not as beautiful as the Apple, but I'm looking at the screen, not the housing. It's not as big, but I don't need a larger screen size. The panel itself has been flawless. Much to my surprise, it has no dead or stuck pixels, no backlight bleed, no red "stained" borders that some LGs have experienced, and no ghosting when moving windows and icons around. It was a gamble, and it paid off splendidly.

Or so I had thought. In the past week I had noticed that two icons, namely "Music" and "TextEdit" in the Dock kept showing up in my login screen. It was just obvious enough to be the tell-tale signs of image retention. After 2.5 years of use, I suppose it was time for something to finally give. Here's a partial shot of how I arranged the icons in the Dock.

Dock.jpg


The little "tune" sitting inside the Music icon and the outline of the pen in TextEdit would show on the grey background when I am at the login screen, nothing else. Mail and System Settings showed no such persistence. Once you see these things, you can't unsee them, and I couldn't let this stand.

I pulled up one of the IPS image retention fix videos on Youtube and let it do its thing. The two partial ghosted icons would show up anytime the video would fade to grey, much like the grey color of my desktop background at the login screen. I've spent the past three days running these videos, yet the ghosting continued, vexing me like a foul pox. I was working on Apple's solution, created a white JPEG, and set the screensaver to run it. I wasn't optimistic, assuming that my fancy "Retina" monitor would forever be haunted by these two icons.

The last thing I did was to move the two offending icons to the other side of the Dock, just to make sure they wouldn't continue to persist, even though the monitor had spent most of the day displaying various image patterns. After that, I went and ate some McDonald's chicken McNuggets, with Sweet and Sour sauce. I typically eat healthy, but allow myself a bit of fast food garbage on rare occasions.

When I came back from my gourmet meal, I woke up my Mac mini, and got to the login screen...and the ghost images had moved. They moved to where I placed the icons on the other side of the Dock. This was both a relief and a frustration.

For reasons that are beyond me, when macOS displays a grey background, the Music and TextEdit icons partially show through. I assume other icons may do the same, but these are the only two that I am aware of. I spent the past three days trying to diagnose an issue that didn't exist, and was entirely the result of how macOS renders a specific set of icons, when the screen is displaying a grey image. That's not just the login screen with the desktop background, but the screensaver, and Youtube videos. The ghosting was caused by macOS, not a defect with my LG.

I'm relieved that my LG continues to be in perfect shape, I don't want to replace it with an expensive monitor with the same panel technology, but it would have been nice to not have wasted three days running a pixel tester had I known that my operating system was the cause.

I am sharing with you the lesson of Colstan's folly. No matter how much knowledge you think you have in an area, no matter how good you are at troubleshooting, no matter what you think you know, there's always the chance of an alternative explanation, and you could be wrong.
 

theorist9

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OLED displays are at a significant risk of permanent burn in, they lose their brightness over time, relative to the pixels next to it, because they are self-illuminated.
....and because they are organic. Micro-LED should be much less susceptible to this.
For reasons that are beyond me, when macOS displays a grey background, the Music and TextEdit icons partially show through. I assume other icons may do the same, but these are the only two that I am aware of. I spent the past three days trying to diagnose an issue that didn't exist, and was entirely the result of how macOS renders a specific set of icons, when the screen is displaying a grey image. That's not just the login screen with the desktop background, but the screensaver, and Youtube videos. The ghosting was caused by macOS, not a defect with my LG.
Does this go away if you do Sys Pref -> Accesibility-> Display -> Increase Contrast? Doing that defeats transparency, so I'm curious if it has an effect on this.

I am sharing with you the lesson of Colstan's folly. No matter how much knowledge you think you have in an area, no matter how good you are at troubleshooting, no matter what you think you know, there's always the chance of an alternative explanation, and you could be wrong.
You are not alone. I had a stick blender that gradually slowed and then stopped working. At first I thought it was the blender itself but, after careful diagnostics, I traced the issue to the charger. When I went to pack up the charger to send it back for replacement, I realized the cord that plugged into the wall right behind the charger didn't belong to it. The reason my blender stopped working is that I had unplugged it about a month prior, and forgot to plug it back in (the battery apparently lasts a long time).
 

Colstan

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....and because they are organic. Micro-LED should be much less susceptible to this.
Which is why I think it's kinda nuts that gamers are ready to pony up $1,000+ USD on these new OLED monitors. Unless they use them for nothing but media consumption and gaming, they'll be looking at replacing them within three years, I would imagine. LG has been dancing around the longevity issue and concentrating on specs.
Does this go away if you do Sys Pref -> Accesibility-> Display -> Increase Contrast? Doing that defeats transparency, so I'm curious if it has an effect on this.
I just gave this a go. No difference. I also tried to take a screenshot but the "ghost" icons don't show and are only visible on-screen. They're too dim to take a camera shot, either. It's quite odd, to say the least.
The reason my blender stopped working is that I had unplugged it about a month prior, and forgot to plug it back in (the battery apparently lasts a long time).
It's remarkable how many things seem obvious, yet have an entirely unexpected answer. I could write an entire series of posts called "Colstan's follies".
 

Yoused

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I have an iPad Air 2 that I bought in the first month it was out and used happily for 5 years, until one full plane of the display went bad. I could still see the colors, they were just wrong. Greenish. It still works just fine as a device, but it had to be replaced due to the extreme discomfort of I am not colorblind.

But, while it was bad, I could clearly see some burn-in masking, mostly of the browser I was using a lot. So, now I use that browser in the full screen (hidden toolbar) mode that it offers.
 
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