[MacTUG] iMac screen burn-in

[Marlon A. Griffith]

MacFixit, Monday, January 21 2008 @ 01:25 PM PST


Though modern LCDs are generally resistant to screen burn-in (resulting in images that erroneously persist on the display), a surprisingly high number of iMac owners have recently reported the issue. In most cases, the burn-in is temporary and can be easily resolved (the same applies for "stuck pixels). Though the problem can affect any LCD, reports we've received implicate iMacs, specifically aluminum iMacs, most often.

MacFixIt reader Mike writes:

    "I've had my iMac since late Oct, about three months, and last night I noticed while booting up that my 'home' window which I leave open, and Mail, were both etched into the screen. I use a plain blue backdrop and the etching is clearly visible. My brightness is set at only 50% and I use a screen saver whenever possible."

Stuck pixels or burn-in are, obviously, most likely to occur in areas of the screen that display mostly static images: the Dock, the menubar, etc.

The best fix for these issues (that we know of) is the use of an applet called "J-Screen Fix.". The applet runs inside a web browser and works by displaying a specific pattern on the screen for several minutes. From the J-Screen site:

    "To reduce screen burn-in: Disable your screen saver. Launch the JScreenFix applet (below) and enter fullscreen mode. This is achieved by pressing F11 in most browsers, if this fails you will need to consult the documentation for your Internet browser. It is important that JScreenFix fills the screen fully or you may suffer additional unequal burn-in. Leave the applet running for about an hour and observe the results. If you notice an improvement, continue running JScreenFix until the burn-in is more acceptable."


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iMac screen burn-in
Authored by: Rosyna on Monday, January 21 2008 @ 03:05 PM PST

I believe this is a feature of hibernation in Mac OS X. It stores a grayscale image of the current screen to the nvram when sleeping and displays that when restoring the sleep image.

This saved screenshot may be shown in other cases as well.

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iMac screen burn-in
Authored by: johnsawyercjs on Monday, January 21 2008 @ 04:51 PM PST

I've seen a few appearances of the type of stored screen image that Rosyna describes, faintly visible, which disappears later. I don't know what purpose it serves, but it seems to do nothing except puzzle and alarm people, because I can't figure out any benefit.

I'd doubt if the Aluminum iMacs are old enough to suffer real screen burn-in, so a stored image is a more likely explanation for at least some people. I didn't think NVRAM was big enough to hold an entire screen image, but with a reduced number of grays (256 shades?), maybe so.

To reset NVRAM, power off the Mac, then power it up, and before the screen lights up, hold down Command (Apple)-Option-P-R, until the Mac has chimed two more times.


iMac screen burn-in
Authored by: NFF on Monday, January 21 2008 @ 08:36 PM PST

LCD screens are physically incapable of burn-in. CRT monitors have individual phosphor dots for each pixel, each of which emits less and less light for a given electron irradiation in inverse logarithmic proportion to the total amount of light they have emitted over their lifespan. In other words, the phosphor dots that are lit the most frequently are the ones that will 'fade' the fastest, and this unequal fading of intensity is known as burn-in.

The pixels in an LCD are NOT individual phosphor dots - they are liquid crystals which twist the amount of polarization of the light they let through from a (usually) fluorescent backlight. This, in combination with two polarized screens results in variable intensities of light that each pixel lets through. As far as we know, liquid crystals have a nearly infinite lifespan, and do not lose their polarizing ability over time. The only component that wears over time on an LCD monitor is the backlight, and that fades uniformly, regardless of which pixels happen to let more light through them.

I don't know what's causing the ghost images, but I would bet it is not the display itself - they should try hooking their monitors to a completely different source to see if the images are still there.


iMac screen burn-in
Authored by: Hillstones on Monday, January 21 2008 @ 11:09 PM PST

More BS from Macfixit. An LCD screen is incapable of burn-in, as the other user also mentioned.


iMac screen burn-in
Authored by: sprocketwerks on Tuesday, January 22 2008 @ 02:42 AM PST

I don't have an iMac but do own an Apple LCD 23" and it has a ghost image of my desktop picture every time I run any app full screen. Also said monitor was hooked up to 2 different machines for testing.

It's pretty annoying when watching movies full screen with that burn in/ghosting effect.


Screen "burn-in": it's real
Authored by: justamacuser on Tuesday, January 22 2008 @ 03:12 AM PST

The same effect ("visual residue") happens on a set of 20" DELL LCD screens i'm using. After a few hours of working in the same setup (3D software with palettes spread out over the whole screen, never being moved around) the close/iconize/optimize buttons and the title bar of the pallettes are clearly visible near the top of each screens, after the program is closed.

I'm using a "monochromic" uniform gray as a background, and the "darker" edges of the window frames remain as purple-ish shadows for an hour or more. This is usually gone after a few hours of the screens turned off. It's noticeable only near the top edge, where most of the heat concentrates (the surface reaches about 40-45 deg. C there, with the backlight source right behind and the warm air moving vertically through the screen), so maybe the liquid crystals simply "settle in place" and take time to properly "loosen up" again.

I also had a 19" TFT of a 2002 build being replaced under warranty after two years because the "icon ghosts" of the desktop didn't disappear any more.

So while it may not technically be a "burn-in", its look surely qualifies as "burn-inny".


LCD 'burn-in' can happen
Authored by: Richard G. Hallas on Tuesday, January 22 2008 @ 03:49 AM PST

It seems to depend on the make of the LCD panel, but it can definitely happen. On my Macs and Apple monitors I've never seen it, because I assume that they're among the better quality display panels. However, on another computer I have (not a Mac, not a PC), I have a Sharp 20" LCD monitor (1600x1200) dating from 2003 (I think), and it definitely shows burn-in. That computer has a number of usually static screen features (icon bar, scrolling news ticker etc.), and on the occasions when they're not there. I can see permanent ghosts of where they've been. This has always been a bit of a 'funny' monitor (I was given it, so I can't really complain!), and I've noticed that it has a tendency to show a ghost of a window after a surprisingly short time; though a ghost that appears after a short time also vanishes. It may be that the more permanent ghosting would return to normal after a while if another image were displayed; I don't know. The image persistence may just be a characteri
stic of the manufacturing process of the screen, and not be permanent after all. But it's unquestionably possible to see burn-in-style effects on this particular LCD monitor.



iMac screen burn-in
Authored by: Wiz on Tuesday, January 22 2008 @ 06:03 AM PST

>From http://docs.info.apple.com/article.html?artnum=88343

In the rare event that an image does become persistent, you can usually get rid of it by following these steps:

1. Temporarily set the Energy Saver sleep setting to 'never sleep'.

2. Display an all-white pattern across the entire display for the same amount of time that the persistent image had been displayed on the screen. To do this:

- 1. Create an all-white screen in a graphics application such as AppleWorks or Photoshop, and save it as a JPEG file.

- 2. Use this as the image displayed by the screen saver.

- 3. Turn the display brightness down (but not off) to preserve backlight bulb life.

3. Verify that the persistent image is gone.

4. If necessary, repeat the process until the persistent image is gone.

5. Restore the Energy Saver settings.


iMac screen burn-in
Authored by: MarkALeeds on Tuesday, January 22 2008 @ 09:29 AM PST

I was also under the impression that it was impossible to get burn-in on LCD's. At work we have 30+ LCD monitors, 12 of which are always on and all 12 have this image burnt onto their display. No idea what causes it but if you exit the browser and display a blank document, then you can very easily read all the static content that was in the browser window.
What you call it I don't know but to all intents and purposes it looks exactly like burn-in on old CRT's.


It's technically capacitance.
Authored by: kucharsk on Tuesday, January 22 2008 @ 04:34 PM PST

When pixels in an LCD display are set to a particular position for a long period of time, they can develop an issue where they want to stay in that position, creating a burn-in like effect.

However, the problem is always resolveable by exercising those pixels in a slightly different way.

It may take weeks or months of course, but the problem will eventually go away.

Note that I'm somewhat surprised by this, as most panels made over the past few years no longer suffer from the issue.


iMac screen burn-in
Authored by: pupspals on Tuesday, January 22 2008 @ 06:55 PM PST

I've seen many LCD monitors suffer from ghosting at work. Nearly all of them!

But then we realized all we needed to do was set the screen saver to Spectrum (or set the Pictures Folder to your Solid Colors wallpaper preloaded on your mac) & let it run. Those flash several colors on your screen which tends to clear the ghosting. You may have to run it for a while, but once it's clear, if it's your screen saver you're usually good to go!


iMac screen burn-in
Authored by: iGreg on Tuesday, January 22 2008 @ 08:10 PM PST

I have indeed seen burn-in on an LCD screen. It may be more rare than on CRT, but I have seen it, and the IT guy at work was surprised but agreed it was burn-in and replaced the LCD.


iMac screen burn-in
Authored by: KurtTappe on Tuesday, January 22 2008 @ 09:20 PM PST

We see this regularly on our 100 iMac production floor. The solution is much easier than anyone else has suggested: Turn the iMacs off for a while. The term I've heard used for the phenomenon is "pixel fatigue" and by resting the screens for 24+ hours, the images go away and all is well again. Easiest to do this on weekends--have users shut down Friday evening and things will be fine again on Monday morning. At home: Turn your Mac off for a day and go outside for a change. ;-)