Instructions
Thinking to yourself, I want a fullscreen of a specific color or I want to test the uniformity of my phone? Click the fullscreen button to make your screen a solid color. Afterwards, click anywhere or press any key to exit the fullscreen mode.
Have a new device that you want to test? Whether you're worried about pixel defects like dead or stuck pixels, backlight bleeding, gray uniformity, color uniformity, clouding, vignetting, dirty screen effect, IPS glow, OLED mura, OLED banding, burn-in, image retention, or other issues, this site can help you test for them.
One of the most important things about testing for screen defects is knowing what type of panel you have. If you're on a phone, most mid range and premium phones nowadays come with OLED panels. Most tablets, particularly iPads, come with LCD panels. Most computers and monitors also come with LCD panels.
Knowing what panel your device usually has is all very well and good, but how do you find out what type of panel you have?
If you're interested in your monitor, your monitor manufacturer will provide information on what type of panel your monitor has. If your screen is part of a finished product, you may have to look up the particular screen. Many laptops will use different types of panels for the same model.
Sometimes the type of screen will be advertised on the product page. If it's not, you may have to search extensively on the manufacturer's website for the parts list. If you are on a computer, you can also look up information about your screen using EDID (Extended Display Identification Data). If you're on a computer, you can use HWiNFO to find out what type of panel you have. Once you have more information about the panel, you can look up the panel in panelook to find out more about the panel.
LCD and OLED panels have many subtypes. For example, LCD panels can be IPS, VA, or TN. LCD panels can also differ in the backlighting technology used, such as edge-lit, direct-lit, or miniLED (sometimes also called local dimming). OLED panels can be Pentile, WOLED, QD-OLED, or RGB. Most phones with OLED will be pentile. These are just some of the many subtypes.
A dead pixel is a pixel that is permanently off. If you use a white background, it will show as a black dot. Bright pixels, sometimes also referred to as hot pixels or stuck pixels by others, are pixels that are permanently on. If you use a black background, they will show as white dots. Both of these are called full pixel defects as opposed to stuck pixels which are often called subpixel defects.
Depending on your manufacturer and how many defects you have, you may be able to get a replacement if your device is still under warranty. HP is much stricter than Lenovo and Dell towards full pixel defects for their monitors. Many manufacturers make a distinction between a dead pixel and a dead subpixel. In almost all cases, three subpixels make up a pixel. All three subpixels must be dead for it to be considered a dead pixel. Likewise, all three subpixels must be bright for it to be considered a bright pixel.
In most cases, dead pixels and bright pixels are not fixable. However, depending on the root cause, very rarely these pixels can be fixed. If you can turn a dead or bright pixel into a stuck pixel, it's likely the root cause is not unfixable.
OLEDs should not be susceptible to bright pixels. Some OLEDs have different subpixel layouts.
A stuck pixel is a pixel that is permanently the wrong color. If you use a black or white background, it may show up as a colored dot or sometimes as a very small black dot. Stuck pixels are caused by subpixel defects. Subpixels are the red, green, and blue elements that make up a pixel. If one of these subpixels is permanently on or off, it will affect the color of the pixel.
If you're under warranty, you can try to get it fixed by the manufacturer. Manufacturers have different policies on how many subpixel defects you need before they consider your screen defective.
If you're not under warranty, you can try to fix it yourself. There are many methods to try to fix stuck pixels, but none of them are guaranteed to work. You can try letting the screen rest for a while or use a stuck pixel fixer. If you're willing to take a risk, you can try applying very slight pressure to the screen. If you're willing to take even more risk, you can try the methods from the accepted answer from this question on superuser.
Backlight bleed is when there is a failure in how a LCD screen tries to block light, like it does when trying to show black. On a black background in a dark room, you may see light bleeding in from the edge and corners.
LCDs will have a backlight, a layer of liquid crystals, and two polarizing filters. The backlight lights up your screen. The liquid crystals, in combination with the polarizing filters, control how much light passes through. However, this arrangement is not perfect. This arrangement is not able to block all the light, causing higher black values (how much light your screen emits on a fully black background) than OLEDs. This is normal operation.
Backlight bleed usually happens when there are problems with the position of the light blocking layers. If those layers are not positioned properly, excessive light will bleed through from the areas not covered.
You can try to get it warrantied, but backlight bleed is not often considered a major defect. In case you can't get it warrantied, turn up the lights and try to ignore it.
OLEDs do not have a backlight and so do not have backlight bleed.
Poor uniformity is a defect in the screen that shows up as areas of different brightness or color on the screen. No screen is perfect, but sometimes manufactures can make particularly bad screens. Clouding, vignetting, and dirty screen effect are all names for particular patterns of uniformity defects. Brightness uniformity can be checked with black, 5% gray, 50% gray, 95% gray, and white backgrounds. Color uniformity can be checked by each color that you've noticed problems with.
Poor backlight placement, backlight variances, miniLED variances, liquid crystal variances, OLED variances, variation in the driving electronics, variation in the electricity supplied to each part of the panel, pressure on the layers, any imperfection can cause poor uniformity.
IPS glow is effectively an inherent aspect of IPS LCD panels. On a black background in a dark room, you may see a uniform glow from the edges or corners. You can distinguish this from backlight bleed by the uniformity of the light and by checking whether or not the light intensity is strongly affected by distance from the screen and/or viewing angle.
VA and TN LCDs do not experience this issue. Only IPS LCDs experience this issue.
It's suggested by some that IPS glow is caused by elevated black levels and/or distortions caused by viewing angle differences on different parts of the screen.
OLED mura is a screen defect where the screen shows up as a grainy texture. To check for OLED mura, use a 5% gray background or a 50% gray background and look for a grainy texture. You will not see this issue on a black screen.
OLEDs and microLEDs are susceptible to mura because each single subpixel is its own light source. Each subpixel will have its own brightness and color. With poor pixel level uniformity, the screen will show this grainy texture. Calibration during manufacturing can help reduce this effect. LCDs almost never have this issue.
Burn-in is when a ghost of an image is burnt into the screen. Burn-in can be checked by using additive primary colors, white, and 50% gray. Burn-in doesn't happen on LCDs. Burn-in is a common problem with OLEDs. OLEDs are susceptible to burn-in because the organic compounds that make up the pixels degrade over time, thus causing the pixels to output less light. For instance, if you have a blue square in the middle of the screen all the time, the blue pixels will degrade faster than the other pixels. This can eventually cause the square to be visible on the screen due to the loss of uniformity.
CRTs and plasmas are also susceptible to burn-in by a similar mechanism involving phosphors.
Although LCDs do not get burn-in, they can get increasing uniformity issues over time, as shown by rting's longevity test.
Want to reduce monitor glow or reflections for a meeting? Want to reduce distractions? Or do you just have a favorite color and want to just stare at it? Tired of having to waste data and processing power using a video or storage space installing apps just to do something as simple as setting your screen a single color? Use your browser instead! Set your screen to a single color here.
Color psychology suggests that viewing certain colors may have subtle effects on your mood and behavior. Red in particular has been shown to have observable effects, stated in this review. Colors such as blue and green have also been studied and seem to have effects. Experience the effects of these colors for yourself.