Green Screen
Open a solid full screen green on any device. Green is the color your eyes read best, so it finds stuck pixels and uneven areas faster than any other test color.
Opens a solid green screen. Look for dark dots, colored dots and patchy areas.
A Solid Green Screen, Online
This page fills your display with plain green. Press the button, the page goes full screen, and the browser and the rest of the site get out of the way.
It is pure green: the green part of every pixel at full power, with red and blue switched off. That is what makes a blank green screen useful for checking a panel.
The color is drawn at the size of your screen, so it fits whatever you open it on. There is no image to scale and no 16:9 file to letterbox on a phone, and a bright green screen looks the same on a laptop as it does on a 4K TV.
Press the button and you get a green screen full screen, exactly as wide and as tall as your display, whether that is a watch-sized window or a television across the room.
It stays there until you press Escape. Nothing moves and nothing flashes.
What a Green Screen Shows You
Green lights one third of every pixel and leaves the other two dark, which finds a very specific set of faults.
Pixels Missing Their Green
A pixel that has lost its green part shows as a dark dot here and looks completely normal on red and blue. This screen is the fastest way to find one.
Stuck Pixels
A pixel stuck on red or blue stands out against green as a small colored dot. Between the red, green and blue screens, every stuck pixel shows up somewhere.
Uneven Color
Green is where a tired panel gives itself away. Patchy areas, or a green that goes flat in one corner, show clearly on a flat field of it.
Dust and Marks
Dust and smears sit on top of a strong color just as they do on white, so this doubles as a second look at anything you spotted earlier.
Cable Faults
A failing video cable often drops one color channel. If green looks patchy while red and blue are fine, swap the cable before you blame the screen.
Part of a Full Check
Green answers one question about a panel. The full color test steps through nine colors and covers the rest.
Why Green Finds Faults First
If you only have time for one color, make it green. Your eyes are built for it.
Human sight is far more sensitive to green than to red or blue. Roughly two thirds of the brightness you see in a normal picture comes from the green part of each pixel, which is why a screen dropping green looks broken while a screen dropping blue just looks a bit warm.
That sensitivity works in your favour during a test. A small dot, a faint patch or a slight unevenness is easier to see against green than against any other color, and people usually spot a fault here that they walked straight past on red.
It also explains why a green fault is the one that drives people mad. A single pixel stuck on green in the middle of a dark film is far more distracting than the same pixel stuck on blue, and it is the reason this color is worth checking on any screen you are about to buy.
It is also the reason video uses green for chroma key work, and the reason a screen with a green fault is so annoying to live with: green is the color you notice.
How to Use the Green Screen
A minute is enough for a quick check of the panel.
Wipe the Screen
Clean it with a soft dry cloth first. Dust on a strong color looks exactly like a panel fault, and it is the usual false alarm.
Open the Green Screen
Press Open Green Screen. The display goes full screen green with nothing else on it.
Look Across the Panel
Start in the middle, then work out to the corners and along the edges, looking for dark dots, colored dots and patchy areas.
Compare With Red and Blue
A dot that is dark on green but normal on red and blue is a pixel with a dead green part. One that stays dark on all three is a dead pixel.
Press Escape when you are done and the page comes back as it was.
Why Is My Screen Green?
A device that has turned green on its own is a fault, not a setting. Where it comes from depends on what you are looking at, so start with the group that matches your device.
Green Screen on Phone
A green tint on a phone, or a phone screen that flashes green when it wakes, has been a known problem on several OLED models over the years. It often appears after a software update and often goes away with the next one.
Check for updates first, then restart. If the green stays, and especially if it started after a drop, it is the panel and it needs a repair.
iPhone and iPad
On an iPhone or iPad, look at True Tone and Night Shift before anything else, since both change the color of the whole screen. Turn them off and see whether the green goes.
A green screen that appears only at low brightness is a panel trait on some models rather than a fault, and Apple support can tell you which.
Android Phones
An Android green screen is worth testing in safe mode, which loads the phone without any app you installed. If the green disappears there, an app is causing it.
Also check the screen mode setting. Vivid and natural profiles push colors around and can look green on some panels.
Laptop or Computer
A green screen laptop fault usually points at the cable or the graphics driver rather than the panel. Plug in an external monitor: if that one looks right, the fault is inside the lid.
Green flickering on a desktop is very often the video cable. Reseat both ends and try a different one.
Old TV Green Screen
An old TV showing a green picture is nearly always the connection. On an older set with red, white and yellow sockets, the green comes from a component cable in the wrong hole, which is easy to do.
On an HDMI set, try another cable and another port before you write the television off.
Green Screen While Watching Video
A green picture with sound, in a browser or a streaming app, is hardware acceleration and not your display. Turn it off in the browser settings, or update the graphics driver.
The give-away is simple: if this page shows clean green and video shows green faces, the panel is fine.
Green Screen for Video: What About Chroma Key?
Most people searching for a green screen want the other kind: the cloth behind a presenter that gets swapped for a beach in the edit. That is chroma key, and it is worth being clear that this page is not that.
A display makes a poor chroma key backdrop. A screen gives off light rather than reflecting it, so it spills green onto the subject and often shows banding or a moire pattern to the camera. A phone or a monitor behind your head will not key cleanly, however green it is.
For real chroma key work you want a matte surface that reflects light evenly: a fabric backdrop, a pop-up panel, or a wall painted in chroma key green. Even lighting matters more than the exact shade, and the usual advice is to stand a metre or more in front of it so the green does not bounce back onto you.
Green is used rather than blue because camera sensors capture more green detail than any other color, which leaves a cleaner edge. Blue is still used when a subject wears green, and some studios keep both.
People do try it. Propping a tablet behind your head as a mini green screen for a video call is a common idea, and it disappoints for the same reasons: the light spills, the edges glow, and the camera sees a slightly different green than your eyes do. A cheap piece of green fabric beats any screen you own.
The exception is a large LED wall, which film studios now use in place of a green screen entirely. That works because the wall shows the real background rather than a color to be cut out, and it costs about as much as a house.
Where this page does help is checking the screen you edit on. If your own monitor has a green cast, every color decision you make on it will be wrong.
Other Color Screens
Green answers one question about a panel. These cover the rest.
Red Screen
The red part of every pixel, and a soft light for night vision.
Blue Screen
Good for banding and uneven dark areas.
White Screen
Dead pixels, dust, cracks and marks on the glass.
Black Screen
Stuck pixels, bright dots and backlight bleed.
Gray Screen
The best background for uneven brightness and burn-in.
Screen Color Test
Steps through nine colors, green included, one at a time.
Frequently Asked Questions
How do I get a full screen green?
Press Open Green Screen. The page fills your display with solid green and hides everything else. Press Escape to come back.
What does a green screen test show?
Pixels that have lost their green part, pixels stuck on red or blue, patchy areas, dust and cable faults that drop one color.
Why is green the best color for finding faults?
Your eyes are far more sensitive to green than to red or blue, so a small dot or a faint patch is easier to see against green than against any other color.
Can I use this as a chroma key green screen?
No. A display gives off light instead of reflecting it, so it spills green onto the subject and will not key cleanly. Use a fabric backdrop or chroma key paint for video.
Why does chroma key use green and not blue?
Camera sensors capture more green detail than any other color, which gives a cleaner edge. Blue is still used when the subject is wearing green.
Why has my phone screen turned green?
Often a software problem after an update, so check for a newer update and restart. If the green stays, especially after a drop, the panel needs a repair.
Why is my old TV showing a green picture?
Usually the cable. On a set with coloured component sockets, a plug in the wrong hole gives a green picture. On HDMI, try another cable and port.
Video plays green but the rest of the screen is fine. Why?
That is hardware acceleration in your browser or player, not the display. Turn it off in the settings or update your graphics driver.
Does the green screen work on a phone or TV?
Yes. Open the page in any browser and go full screen. It matches whatever screen you open it on, with no image to scale.
Is this green screen free?
Yes. It is free, it needs no app and there is no account to make.
Open a Green Screen
One button, one full screen of solid green, and Escape to come back.
Free, no app to install, and it works on a monitor, laptop, tablet, phone or TV.
Open Green Screen