Green Screen
A plain green screen. Go full screen, then press Esc to come back.
Look over the whole screen for dots that stay a different color.
Use your monitor or phone controls to raise the brightness. To come back, press Esc or click Exit full screen.
Ready.
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How to use this test
A full-screen green page for checking the green channel of a display and spotting stuck pixels. It can also stand in as a plain chroma-key background on a second monitor or tablet in a pinch, though a cloth screen gives better results.
Press Go full screen and inspect the whole display. Compare with the red and blue pages to identify which sub-pixel is at fault. Press Esc or click Exit full screen to return.
What the results mean
The green should be uniform. A dark dot that is fine on red and blue is a dead green sub-pixel. Because the eye is most sensitive to green, faint uniformity differences show up here first.
Common questions
Can I really use this as a chroma-key background?
For a small subject such as a product or a hand, a tablet or monitor at full brightness can work. For a person you need an evenly lit cloth or painted wall; a screen is too small and reflects.
The green looks different on my phone and my monitor.
Displays cover different color ranges and are calibrated differently. The page sends the same pure green to both; the difference is the hardware.
Is it the same green as film studios use?
It's pure digital green, which keying software handles well. Studio screens are chosen for how they reflect light rather than for a particular code.