Why do we use green screens?

597 views

I don’t understand why we can’t have red screens or black screens.

It’s just green for some reason.

In: Technology

5 Answers

Anonymous 0 Comments

Imagine you had a bar that one side is blue and it slowly turns yellow from left to right.
At some point it’s green in the middle.
If I asked 10 people to point at the bar where exactly it turns green people would pick different points.

This shows that picking where a colour starts and ends can be tricky.

For image editing software, if you want to place a person in front of an imaginary background the software needs to clearly and quickly tell where that person ends and the background begins. The green screen is such an artificial colour it’s not like anything someone is likely to wear. So the computer can easily tell the by the contrast of the person’s clothes, hair, skin etc and the green screen.

If the person or subject or whatever you want to use is green and blue screen is used.

It’s all about an immediately obvious contrast of what you want and the background.

Anonymous 0 Comments

It can be any colour.

But you need it to be a colour that won’t interfere with the subject you’re shooting- if you wear a green shirt in front of a green screen it will erase the shirt too.

Both green and blue screens are used in the film/tv industry.

Anonymous 0 Comments

The technology is called chroma keying. With it, you can select a color and video software will select that color (you can choose the tolerance) and delete those pixels. So the color doesn’t need to be green. We also have blue screens. Whether one should use blue or green screen depends on the lighting of the subject and the scene that will replace the original.

We choose between blue and green screens because those are the colors that are not present in human skin. Anything with red or orange would easily spill over the skin and delete parts of the subject in front of the screen.

Anonymous 0 Comments

The simple reason green and blue are used most frequently is skin tones don’t have green or blue in it. So when you go to replace the background you won’t accidentally make someone disappear (unless you want them to, so you give them something green or blue to wear).

Anonymous 0 Comments

Theoretically any colour can be used for background screen as long as it is not used by objects/actors in front of them.

A red screen is bad idea because in some light conditions, parts of human skin can look rather reddish. Also red and blue are very common colours in clothing, meaning whole wardrobe design needs to be changed and severely limited.
Black just doesn’t work as it’s the colour of shadows, eyes, hair, shoes etc.

Bright green is not very common colour in clothing, can easily be spotted and separated by post processing. So that’s what’s used most often.