How Does Green Screen Work

How does green screen work? The technology is a popular and easy way to add something magical to your event or publicity images. But for something so often used, we often overlook how it all comes together.

Chroma key compositing (or chromakeying) is a technique used to layer two images together based on colour hues. The process takes a video and removes a specific colour, effectively making it transparent, and a predetermined backdrop is layered over the space. Therefore, the subject blends seamlessly onto the new background, creating the final look of a location shoot without the necessary logistics or expense of leaving planet Earth!

demonstration of how green screen is set up to use chroma key isolation. Subsequent compositing is simpler when the subject contrasts against a flat background color.
This image shows how a green screen is set up for subject extraction

When this technique was first popularised, blue was the preferred colour, though now more people prefer to use green screens. These colours are used because they are incredibly different from skin tones and are least likely to be found in clothing. Green is preferred as blue is more often found in clothing and eyes, current cameras are more sensitive to green than any other colour, and it is easier to illuminate. Thanks to the latest software, any colour can be used in chromakeying.

Green screen can also be used on objects: many of the CGI creatures we see today are actually filmed with green-covered figures or people, to be replaced later with their fully-rendered counterparts.

How does green screen work in today’s photography environment? And what’s changed? Chroma key technology is currently available everywhere, including on your smartphone or tablet. There is a variety of software for the beginner to professional photographer to easily create and edit their own green screens and backgrounds. Special FX no longer belong solely to the realm of the professional videographer; you can make you own effects with a computer, a digital camera and green screen software, all at more affordable prices.

To make the most out of your green screen, ensure that:

  1. The colour of your screen is as far removed from the items in your shot as possible.
  2. The screen is well illuminated to eliminate any shadows.
  3. Ensure the surface is flat and smooth. Using a tension screen or painting a flat surface are great ways to do this.
  4. Avoid reflections. Shiny objects could pick up the green screen light and make it difficult to key correctly.
  5. Set your subject lighting contrast ratio as well as key / fill placement, to match the background you will be bringing in.

Poppy’s Photobooths has a variety of green screens and software available to make your event truly magical. Check out our photo booths and select the setup that works best for you. How does green screen work? Absolutely seamlessly, when we set it up for you. Green screen technology can be included with all of our photo booth hire. We can transfer you to Westeros or Hogwarts, or we can load you up with all of our backdrops, moving or still, so you don’t have to change a single backdrop to have all kinds of adventures!

Poppy's Photobooths