What is Dirty Screen Effect?


When buying a new TV, you may experience poor color uniformity on a black background, also known as “dirty screen effect” or DSE for short. So what is causing this and is there anything you can do about it?

What is Dirty Screen Effect?

Dirty screen effect refers to the uneven appearance of a solid color, especially gray, black or white backgrounds on a display panel. It can affect anything with a thin, modern screen, from TVs and monitors to smartphones and laptops. The effect is named because it looks like an opacity on the screen under the right conditions, as if the screen needs cleaning.

You can spot the dirty screen effect by using full screen solid colors on your TV. Under normal viewing conditions, you may only notice the effect in very dark or very bright scenes. It may only be visible in a very dark room. Sometimes movements like camera pans (especially on solid colors, like the green field in a sports game) can bring out the effect.

DSE primarily affects LED-lit LCD panels, but similar effects to DSE can also be seen on OLED screens. On LCDs, this is due to manufacturing issues with the panel itself or uneven backlighting. In some cases, you may be able to see the LED backlight grid behind an assembly that uses full local dimming.

On an OLED, the effect means either a faulty panel or a stripe that often stands on nearly black content. Taking a photo of your screen with a smartphone will almost always exacerbate the effect compared to real-world viewing conditions.

You may have heard the term “panel lottery” used to describe buying a new TV. If your set shows signs of DSE, the “good” news is that very few panels look perfect when examined on gray, white, black, or even full-field color slides.

What can you do there?

Before you rush out to test your TV’s panel uniformity, consider this: if you don’t see any variation in real-world viewing conditions, your panel is probably good enough. Many TV owners don’t notice a problem until they look for it, in which case they notice blemishes or issues that are then hard to ignore. The same goes for OLED sets with dark bands and patches.

If you absolutely must test every facet of your TV, do so when you first buy it so you can immediately make a warranty claim. In the case of an OLED, you may be required to “run” it for a few hundred hours or run a pixel refresh cycle to alleviate banding issues before your request is honored.

There is nothing you can do to reduce the appearance of DSE on an LCD since the problem is a manufacturing issue. Websites like RTINGS test each set for phenomena and publish their results online, but differences can occur between different products of the same model, which were manufactured in the same year, in the same factory. It’s a panel lottery!

If under test conditions your TV shows some DSE or your OLED shows visible banding, try to get rid of it. If you don’t pay attention to it, you may find that it is easily ignored and not even noticeable when watching movies, streaming TV shows or playing games.

If that really bothers you and your TV’s warranty has expired, well, there’s always buying a new TV. Of course, you will take yet another round of the panel lottery.

Buying a new TV?

If you want a new TV, be sure to read our modern TV buying guide (and our gaming TV buying guide, too). We’ve also produced a buying guide for the best TVs you can buy.

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