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The Science Behind: Green Screens

Cover Page - Ishita Baghel

We've all seen fiction movies. Harry Potter, Percy Jackson, the Avengers, etc, etc.

I hate it to break it to you, but some of the characters in those movies aren't real.

  • *Dramatic gasp*

Now, you might say that you saw Dobby the elf with your very own eyes, unfortunately, I have to inform you that it was all an illusion.

All of these high-tech disguises are made with the help of a brightly colored backdrop and a process called "chroma-key", more commonly known as "green screen".

This technique allows technicians to separate the backdrop from the humans in front of it and replace it with almost anything. Like a park filled with dinosaurs. Or a zombie apocalypse.

Once the scene has been recorded the computer takes the computer output and removes a single color. This color is typically bright green because it stands out against human skin tones and is not usually found in clothing.

For chroma-keying to work, the background must be one single color have no shadows. Once the green is identified by the computer, it can be replaced by almost anything.

Not only backdrops but also objects.

Remember Dobby the elf?

Dragons, fairies, centaurs, gargoyles, mermaids, unicorns, monsters, and many more can be created using this method.

The use of this process has become advanced over many years. It can now be used for something as small as a hair on an actor's head.

At the same time, chroma-keying is also available for the use of the general population. Apps like Photoshop, After-Effects, and iMovie make it possible for anyone with a green screen to create what they like.

However, this fascinating technology is not always used for its intended purposes.

People use it to create fake news and even ridicule public figures.

In 2016, Queen Elizabeth of England celebrated her 90th birthday. She wore a green outfit and the next day the internet was filled with memes and jokes from people who had altered her clothes.

As all technology often is, the green-screen is a double-edged sword. While the people of Hollywood can use it to create the wonderful fiction moves we see today, jokesters can use it to fool people.

So next time you wear green, beware of the modern use of the green screen.

Until next time...

Stay Curious ;)




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