How to use the green screen test
- Dim the room lights and set your screen brightness to maximum.
- Press Pure green to fill the whole screen with solid green.
- Scan the panel slowly from corner to corner for any dot that is not green, such as black, yellow, cyan or white.
- Look for patches that are bluer, yellower or grayer than the rest, which point to uneven color across the panel.
- Press Esc, then try Studio green and check that the shade stays even.
- Tap anywhere or press Esc to exit.
What a green screen shows
| What you see | Likely cause | What to do |
|---|---|---|
| A black dot | Dead green subpixel, or a fully dead pixel | Run the White Screen Test. If the dot stays black on white too, the whole pixel is dead. |
| A yellow dot | Red subpixel stuck on | Note the position, then confirm it on the Red Screen Test. |
| A cyan or light blue dot | Blue subpixel stuck on | Check the same spot on the Blue Screen Test to be sure. |
| A white dot | Red and blue subpixels both stuck on | This is a stuck pixel. Compare its position on each color. |
| Part of the screen is bluer, yellower or grayer | Uneven color uniformity | Mild unevenness is common on LCDs. Check it at your normal brightness. |
| The whole screen has a green tint in normal use | Panel fault, low brightness OLED tint, or a color setting | Turn off color profiles and night modes, then retest at several brightness levels. |
Who this is for
- Buying a used phone or monitorGreen is where tint and uneven shading show first. Check before you pay.
- Phone owners with a green tintConfirm whether a green cast or a green line is a hardware fault before you book a repair.
- Just unboxed a new displayLook for off-color dots and uneven patches while the return window is open.
- Video creators and streamersUse Studio green as a quick chroma key backdrop on a spare monitor or tablet.
- Repair techniciansSeparate a stuck subpixel from a panel tint problem in under a minute.
- Anyone filing a warranty claimShow a stuck or dead subpixel on a clean, uniform background.
Frequently asked questions
Why do a green screen test when I already ran a white one?
White lights every subpixel at once, so a subpixel stuck on can hide. A green fill turns the red and blue subpixels off, so one that is stuck on shows as a yellow, cyan or white dot. Green is also where uneven shading is easiest to see.
What does a dead green subpixel look like?
On a green fill it is a small black dot, because that subpixel cannot light up. On red and blue screens the same pixel still glows normally, which separates one dead subpixel from a fully dead pixel.
My phone screen has a green tint. Is this test enough to tell what is wrong?
It helps. If the whole screen looks green on the white test, the cause is usually a color setting or a panel fault. If the tint only shows on dark or dim content at low brightness, that is a known trait of some OLED panels. Test at several brightness levels and turn off color modes first.
The screen looks pink or magenta in some areas on green. What does that mean?
Pink or magenta is the opposite of green, so a patch that looks pinkish on a green fill means that area is showing less green than the rest. That is a uniformity problem, often along an edge, and mild cases are normal on LCDs.
Can I use this as a green screen for video?
Yes, as a quick backdrop. Studio green is a common chroma key shade. A lit, evenly colored monitor behind you is a handy backdrop for a small setup, though a real green backdrop with even lighting gives cleaner results than a screen.
Why does Studio green look duller than Pure green?
Pure green uses the brightest green your screen can show, which can glow and cast light on skin and objects. Studio green is a softer shade used for chroma keying because it keys out cleanly and spills less light.
Does a green screen test work on OLED and LCD alike?
Yes. The fill and the dots you look for are the same. LCD panels can also show backlight unevenness, while OLED panels can show uneven wear in one area.
What should I do if I find a stuck pixel?
Note its color and exact position, then run the White, Red and Blue tests to see how it behaves. Check the warranty policy, because many makers only replace a panel above a set number of faulty pixels.