What is the dirty screen effect?

A large TV on a wall in a modern house.

Something you may encounter when purchasing a new TV is poor color uniformity on a black background, also known as the “dirty screen effect” or DSE for short. So what causes it and is there anything you can do about it?

What is the dirty screen effect?

The dirty screen effect refers to the uneven appearance of a solid color, especially gray, black, or white backgrounds on a monitor. It can affect anything with a thin and modern screen, from TVs and monitors to smartphones and laptops. The effect is named because it resembles a cloudiness on the screen under the right conditions, as if the screen needs to be cleaned.

You can see the dirty screen effect with solid colors in full screen 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 such as camera movements (especially with solid colors, such as the green field of a sports game) can make the effect stand out.

DSE usually affects LED-lit LCD panels, but similar effects to DSE can also be seen on OLED screens. On LCD screens, this is caused by manufacturing issues with the panel itself or uneven backlighting. In some cases, you can see the grid of LED backlighting behind a set that uses full array local dimming.

On an OLED, the effect indicates either a defective panel or streaks that often crop up with near-black content. Taking a picture of your screen with a smartphone will almost always exacerbate the effect compared to real viewing conditions.

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

what can you do about it?

Before rushing to test your TV’s panel uniformity, consider the following: If you can’t see any variance in real-world viewing conditions, your panel is probably good enough. Many TV owners don’t notice a problem until they start looking for it, only to spot imperfections or problem areas that are hard to ignore. The same goes for OLED sets with stripes and dark spots.

If you absolutely must test every facet of your TV, do so with your first purchase so you can get the warranty right away. In the case of an OLED, you may be asked to “run in” it for a few hundred hours or run a pixel refresh cycle on it to reduce banding issues before your request is granted.

There is nothing you can do to reduce the appearance of DSE on an LCD screen as the problem is with the manufacture. Websites such as RTINGS test each set for the phenomena and post their findings online, but differences may occur between different products of the same model, produced in the same year and in the same factory. It’s a panel lottery!

If your TV shows some DSE or your OLED shows visible stripes under test conditions, try putting it out of your mind. If you don’t pay attention to it, it can be easily ignored and even not noticed when watching movies, streaming TV shows or playing games.

If it really bothers you and the warranty for your TV has expired, you can always buy a new TV. Of course you will participate in the panel lottery again.

Buy a new television?

If you want a new TV, read our guide to buying a modern TV (as well as our guide to buying a gaming TV). We’ve also created a buying guide to the best TVs you can buy.

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