Green Screen
Fills the whole screen with the most saturated green your display can produce. On a wide-gamut screen that is a noticeably purer green than the sRGB #00FF00 most pages can offer, which gives keying software a cleaner color to pull.
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Your browser did not report display-p3 support, so this page is using the sRGB green, #00FF00.
What a screen full of green is good for
- Small objects. A phone, a hand, a product held up in front of a tablet or a monitor keys out about as well as a cheap cloth would, and the screen is already on your desk.
- Head and shoulders at close range, if the screen is big and you are close to it. A 27 inch monitor behind you fills a webcam frame at arm's length and very little further than that.
- Testing a key before you build the real setup - lighting angles, software settings, spill on a collar. It is much faster to learn what your keyer is fussy about with a screen than with a stand and fabric.
- As a flat reference color: checking a camera's white balance behavior, filling a frame for a color test, or giving an editor a solid block to swap out later.
Wide-gamut green, where the browser allows it
The page asks the browser whether it understands the display-p3 color space, using the same CSS.supports check any site would, and paints color(display-p3 0 1 0) when the answer is yes and #00FF00 when it is not. On a display that actually covers P3 - most recent Apple screens, many current laptops and monitors - the wide-gamut green sits outside what sRGB can express and pulls further away from skin tones, which is exactly what a keyer wants. On an sRGB panel the browser may accept the syntax and still show you the nearest color it can, so treat the line below as what the browser reports, not as a measurement of your monitor.
Be honest about what a screen backdrop can do
A monitor is a light source, not a matte surface, and that changes the job in three ways. It glows, so it throws green onto the back of whatever is in front of it - green spill on hair and shoulders is the usual giveaway. It is glossy, so a lamp or a window behind you appears in it as a bright reflection with no green in it at all, and a keyer will leave that reflection behind as a hole. And it is small: to fill a frame it has to be close, which means the light falls off across it and the edges read darker than the middle. Kill every reflection you can see before you shoot, light your subject from the front so the screen does not have to be bright, and keep some distance between subject and screen if the frame allows it.
Green is the default because sensors capture more green detail than anything else, but it is the wrong choice against green clothing, green foliage or anything with a green logo on it. Film and television use blue for exactly those cases, and it also handles blond hair more gracefully. Use the blue screen instead
Frequently asked questions
Why is chroma key green rather than any other color?
Two reasons. Human skin has very little green in it, so a green background is the furthest common color from the thing you are usually trying to keep. And camera sensors devote roughly twice as many photosites to green as to red or blue, so the green channel is the least noisy one to build a mask from. Blue was the film standard for decades and is still the right answer when the subject is green.
Can I really use a monitor as a green screen?
For a close-up subject, yes, and it works better than people expect. For a full body shot, no - you would need a screen the size of a wall, and the reflections and falloff get worse the further back you go. The realistic use is a hand, an object, or a head and shoulders framed tight, with the screen close behind and the subject lit from the front.
How do I get rid of green spill?
Move the subject further from the screen, which is the fix that works even when nothing else does. After that: turn the screen brightness down until the key still holds but the glow drops, light the subject from the front so the screen is no longer the main light on them, and use the spill suppression control your software almost certainly has. Fine hair and translucent edges are where spill shows first, so judge it there.
What software do I need?
Whatever you already use. Video call apps have background replacement built in, OBS has a chroma key filter, and every editor from the free ones upward has a keyer. This page only supplies the background - it does not process video, and nothing you point at the screen is uploaded anywhere, because there is nothing here to upload it with.