How Green Screen Works

BY Marshall Brain / POSTED March 6, 2009
Hammerbrook - City can this really be true?
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With green screen technology, film makers, TV producers and even the YouTuber next door can create all kinds of interesting effects. It used to be that you did everything with film techniques, as described in this article:

How Blue Screen Works

The first Star Wars movie was done using this technology. But computers make it a whole lot easier today.

The best example of green screen from everyday life is the weather person on the evening news. He/She stands in front of a green wall. A computer can tune into the green color and replace every green pixel with a pixel from another image. Of course, if the weather guy happens to wear something green, the computer will perform its magic there too, creating a hole in the person, as you can see here:

The great thing about the technology is that it has become incredibly easy for just about anyone to use it. With a little care the effect looks incredibly real, as seen in this video:

The creator of this video offers this advice:

Made using Adobe After Effects ONLY!

Use Google to find info on it.

Also use Google to find tutorials on Green Screen Techniques. There are loads out there.

Most of the shots are static images that i split into two layers in Photoshop. In particular the city shots; i cut out the buildings i wanted the performer to hide behind and then placed them in separate layers in After Effects. The performer is sandwiched between them.

All the camera moves were done in After Effects by Motion Sketching the whole composition. A wiggle expression on the Position key frames would work just as well.

That’s not me in the video, its my friend Dave.

This was for my final year project at Staffordshire Uni.

It was shot on a Canon XL2

It took about a two weeks to make, on and off.

Check out for my showreel.

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