Chroma keying has become one of the most important tools in the video world today. From compositing in big-budget movies to simply removing the background during a live stream, chroma keying is a technique that has become both more powerful than ever, and more accessible.
In simplest terms, chroma keying is selecting a specific color and removing that color from the footage. One of the most common applications of chroma keying is using a green or blue backdrop, then removing that color from the footage, effectively erasing the background. This allows you to replace the background, or to superimpose the subject onto other composites. The tricky part is getting the cleanest key possible – making sure there are no artifacts left around the edges of the image where the green or blue screen used to be. There are a few ways to help mitigate this issue.
Make sure the green screen is lit evenly on all sides. Uneven lighting will cause different areas of the screen to be different shades of green, making the keying process more complicated and more prone to error.
When you’re hitting a green screen with light, that light can reflect green off the screen and onto your subject, making it difficult to key out properly. Make sure to choose a screen made of non-reflective material, and move the subject away from the screen as much as possible.
A chroma key will be more successful the more data you can provide to the keying software. This includes both video resolution and color data. Higher resolution provides more detail, and more color data provide more shades of each color, allowing for more accurate keying. Many cameras and phones are limited to shooting in 8-bit color formats, which does not provide as much detail as higher quality formats and can result in poor quality chroma keying.
Behind the Scenes
The Final Piece
There are many other steps that can be taken to produce high-quality chroma keying effects, including proper exposure, matching lighting environment to match composite images, limiting motion blur, and using powerful software tools. At Vervocity, we provide chroma-keying as part of our video services and can implement it into video projects to promote your business!