How Does a Green Screen Work?

Used in everything from movie special effects to your local weather forecast, green-screen makes it easy to add, or ‘composite’ elements together to achieve an effect that would be otherwise impossible to create. But how does a green screen work?

Here’s how green-screens work along with some tips for when you might be working with one.

How Green-Screens Work

The process of removing that coloured background is called ‘pulling a key’, also sometimes referred to as a chromakey.

Traditionally, blue was the colour used for chromakeying when working with analogue cameras. However, newer digital video cameras are much more sensitive to information captured in the green channel.

Green or blue are used because they are the two colours that are least similar to human skin tones, greatly simplifying the keying process when working with on-screen talent.


How You Can Use Green-Screen

Some uses of green-screen include: Placing your interview subject over a series of images, logos and text, having a ‘virtual host’ on your website, or simply creating a little extra ‘wow factor’ to your project.

Basetwo Media has our an in-house green-screen production studio which makes it easy to incorporate the effect into any project.

Tips When Working with Green Screen

  • Since we’ll be removing all the green information from the shot, the on-screen talent should not wear anything green if possible. Other, solid colours work best.
  • Highly reflective surfaces such as chrome, polished wood and glass tend to pick up some green reflection, so avoid shiny jewelry, highly polished shoes or reflective props.
  • Since the green-screen must be evenly lit, we have to use a large number of lights which making filming in small spaces a challenge. It also helps to have the talent as far away from the screen as possible to minimize green ‘spill’. We prefer to film in a professional production studio like ours.
  • Very fine details can get lost when the final key is pulled. For this reason we ask that you try to minimize frizzy or fine strands of hair, loose clothing, rapid movements and excessive numbers of people or objects in the frame at the same time. As with most things, simpler is better in this case.

Although there is an added cost to utilizing a green-screen element in your next video production, it is a great way to add production value, and can be just the thing to make your video stand out.