If you spend long enough debating the merits of LCD vs OLED display technologies, eventually someone will touch upon the subject of dreaded OLED screen burn in. The point made is that OLED displays will inevitably suffer from horrible-looking artifacts over time, while LCD and new technologies like Mini-LED won’t. But like most of these debates, you’ll probably hear as many overblown anecdotes as you will actual facts about the issue.

You may never have experienced it for yourself, but many consumers are wary about the possibility of burn in when pondering their next smartphone purchase. Particularly as expensive flagship smartphones have now universally adopted OLED display technology. Apple, Google, and other manufacturers acknowledge that burn in can be a problem in rare cases. OLED technology has made its way to much more affordable price points in recent years too, putting the issue on the radar for even more consumers.

To settle any concerns, we’re going to answer all the key questions — what is screen burn in, why does it happen, and what can I do to avoid it?

Read more: AMOLED vs LCD technology explained

What is screen burn in?

The name “burn in” is a little misleading, as there’s no actual burning or heat involved. Instead, this term is used to describe a display that’s suffering from permanent discoloration across any part of the panel. This may take the form of a text or image outline, fading of colors, or other noticeable patches or patterns on the display. The display still works as normal, but there’s a somewhat noticeable ghost image or discoloration that persists when the screen is on. To be considered as screen burn in, these artifacts have to be permanent and are a defect caused on the display hardware side. Rather than a graphical glitch that may be caused by software, temporary image retention, or a problem with the display driver circuitry.

The term actually dates back to old CRT monitors, where phosphor compounds that emit light to produce images lost their luminance with time. LCD panels can exhibit similar problems, but these are much rarer due to the nature of LCD’s backlight and color matrix design.

Uneven colors and brightness or a 'ghost' image are signs of burn in.

Although not as bad or noticeable as old CRT issues, today’s OLED smartphone displays can eventually suffer from a similar problem. That being said, it’s quite difficult and rare to notice unless you know what you’re looking for, and it takes hundreds if not thousands of hours of screen on time before any such errors will appear. In smartphones, pattern burn in is most typically associated with always-on-displays, and navigation buttons and the notification bar. The example below demonstrates a textbook case:

Although most smartphones now support gesture navigation controls in the place of the old button design. So this type of burn-in is much less of a problem than it used to be.

Why does it happen?

The cause of all screen burn in is the varying lifecycle of a display’s light-producing components. As these parts age, their brightness changes, and therefore the panel’s color reproduction gradually shifts with time. All displays experience some color shift as they age, although this can be mitigated somewhat with clever software. But with burn in, some parts of the screen age faster than others. This can gradually shift the perceivable colors of the screen in one area more than in other, leaving what looks like a ghost image behind.

All displays experience some color shift as they age, but with screen burn in some parts of the screen age faster than others.

With modern smartphone and smartwatch technology, screen burn in can manifest as a result of the different life spans between the red, green, and blue LED subpixels used in OLED panels. As we mentioned before, areas of the display that seldom change, are bright white, or are often black and switched off, such as navigation buttons or the notification bar, are the most likely areas to notice this issue. You may also start to notice the effect in darkened status bars designed to hide display notches.

This is because these areas are more likely to consistently display one color, a set icon, and/or text, while the rest of the display produces a more random selection of colors from various websites, videos, apps, etc, over a long period of use. Therefore the subpixels in these areas see different amounts of use and thus age differently, eventually resulting in a slight variation in color reproduction. Switching to transparent and color-changing bars has the added bonus of evening out the color aging process.

See also: Display refresh rate explained: What does 60Hz, 90Hz, or 120Hz mean?

OLED displays are made up of red, green, and blue LEDs, but the different colors have different lifespans.

Speaking more technically, the issue is that blue LEDs have significantly lower luminous efficiency than red or green pixels. This means that for a set sized pixel, a blue LED needs to be driven at a higher current in order to achieve the same brightness as red or green. Higher current causes the pixel to degrade faster, shortening its lifespan and therefore eventually tinting the display towards the red and green colors. Therefore an OLED display’s color doesn’t degrade evenly, it will eventually lean towards a red/green tint.

So, if one part of the panel spends a lot of time displaying a blue or white image, the blue pixels in this area will degrade faster than in other areas. That’s essentially what burn-in is. Although display manufacturers do account for this in their panel designs.

Can screen burn in be avoided?

At this stage, manufacturers are very aware of the potential issues and have already taken a number of intelligent steps to help avoid burn in. For starters, Samsung has been using its pentile subpixel arrangement (see above) in its AMOLED displays since the Galaxy S3. By making the blue subpixel larger, it requires less current to drive in order to provide the required light. Driving the LED with less current increases its lifespan, such that it takes longer for any noticeable color shift to occur.

This doesn’t directly address the issue of different parts of the screen aging at different rates, but it does mean that it will take significantly longer to notice than with older or cheaper OLED panels. More expensive and modern OLED panels are built with longer-lasting LEDs and well-designed layouts, meaning flagship smartphone displays age slower. These days, it’s cheaper phones packing cheaper displays that are marginally more likely to see issues after heavy use.

Display technology has improved and most consumers can use their phones for years without any sign of burn in.

There are software solutions too. Android Wear product manufacturers can enable the OS’s “burn protection” option. This mode periodically shifts the contents of the screen by a few pixels, so that they spend more equal time displaying different colors. Smartphones equipped with Always-On display technology employ a similar tactic. Google also suggests a selection of design guidelines tailored to avoid any screen burn-in problems when designing for OLED watches. The move towards gesture rather than on-screen navigation controls is also helping to alleviate one of the more noticeable burn in areas.

Huawei Mate Xs review dark mode quick settings

But what can I do, is there a screen burn fix?

If your screen is already burnt in, there’s not a lot that can be done to undo the damage. There are apps on the Play Store that claim to reverse the problem, but these will just end up “burning” the rest of the screen to match the colors, which isn’t really ideal.

If you are concerned about the issue, there are a number of preventative measures that you can take to prolong display lifetime and help to prevent the dreaded ghosting effect:

  1. Keep your display brightness as low as is reasonable. Increased brightness requires more current and therefore shortens LED lifespans. Don’t crank up the brightness unless you have to.
  2. Shorten your screen-off timer. Turning the screen off when you’re not using it will prevent static images from being displayed.
  3. Use Dark Mode, if supported. Using a darker interface reduces the amount of illumination and helps LEDs last longer.
  4. Use Immersive Mode, where available. This hides the notification bar, so static icons won’t be displayed. Alternatively, pick a launcher that offers a similar feature, as well as a transparent navigation bar and app drawer options.
  5. Pick a wallpaper with darker colors and change it every now and again.
  6. Use keyboards that offer darker themes to prevent color degradation in the lower half of the display.
  7. If you use a navigation app regularly for long journeys, pick one that doesn’t have a lot of bright static UI elements.
  8. Switch to gesture navigation and drop the buttons, if your phone supports it. This helps to prevent burn in at the bottom of the screen.

That being said, screen burn in isn’t something that should concern many users if they’re looking to buy a new OLED smartphone. Modern panels have much longer lifespans than early OLED smartphones, and even then burn in was rare. Just don’t leave a static image on the screen 24/7 with the brightness set at max and you can enjoy your displays for years without issue.

The bottom line is that you should be looking at several year’s worth of use out of a modern smartphone display before any screen burn in will be noticeable. But it doesn’t hurt to be aware of what can happen to aging handsets and how to maximize their lifespan.

Up next: Love dark mode? Here’s why you may still want to avoid it