One thing you may encounter when buying a new TV is poor color uniformity on a black background, also known as “dirty screen effect” or DSE for short. So what causes it? Is there anything I can do about it?
What is the dirty screen effect?
Dirty screen effect refers to the uneven appearance of a solid color, particularly gray, black, or white backgrounds on a display panel. It can affect anything with a modern thin screen, from TVs and monitors to smartphones and laptops. The effect is so named because it resembles a haze on the screen under the right conditions, as if the screen needed to be cleaned.
You can detect 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 light scenes. It may only be visible in a very dark room. Sometimes movement like camera pans (especially in solid colors, like the green field in a sports game) can make the effect stand out.
@SamsungUK Could you tell me how this vertical banding/dirty screen effect defect falls within your product specification framework? I’m pretty sure you wouldn’t use these images to promote your 2021 QLED range. Motion on my TV picture (e.g. camera pans) is even worse! pic.twitter.com/lmC9pQYFo2
– Matt Francombe (@FrancombeMatt) October 3, 2021
DSE primarily affects LED-illuminated LCD panels, but DSE-like effects can also be seen on OLED displays. In LCD displays, it 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 a computer that uses full-array local dimming.
On an OLED, the effect means a faulty panel or banding that often rears its head over near-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 array 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 you rush to test your TV’s panel for uniformity, consider this: If you can’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, at which point they notice blemishes or problem areas 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 make a warranty claim right away. 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 mitigate banding issues before your request is fulfilled.
There is nothing you can do to reduce the appearance of DSE on an LCD, as the problem is caused by manufacturing. Websites like RTINGS test each set for the phenomena and post their findings online, but differences can occur between different products of the same model, that were produced in the same year, in the same factory. It’s a panel lottery!
New tv review: @SamsungUK Q900/Q900R 8k QLED. An excellent 8k TV with impressive picture quality. It has wide viewing angles, but the contrast is similar to the Sony Z9F. Unfortunately, the dirty screen effect is very noticeable.https: //t.co/tWXsRRrTLq pic.twitter.com/ENlJq31qQz
– RTINGS.com (@rtingsdotcom) March 27, 2019
If under the test conditions your TV shows some DSE or your OLED has visible banding, try forgetting it. If you don’t pay attention to it, you may easily ignore it and not even notice it when watching movies, streaming TV shows or playing games.
If it really bothers you and your TV’s warranty has expired, well, there’s always the option of buying a new TV. Of course, you’ll be taking another spin on the panel lottery.
Buy a new TV?
If you want a new TV, be sure to read our guide to buying a modern TV (and also our guide to buying a gaming TV). We’ve also put together a buying guide for the best TVs you can buy.