Long before post, before the camera and lighting get set, the background color concerns must be addressed if you wish to capture good, easy to key ‘green’ screen footage.
To begin with, select your keying material and color. Chroma green is the most common, but not the only option, depending on what you will be filming and keying. I once had to use a hot pink color for a book trailer shoot in which I was filming America’s National Parks: A Pop-Up Book with ‘hands-free’ page turning. For obvious reasons green was right out, and blue would have been equally troublesome. The hot pink, which would have been terrible as a keying color for a Caucasian subject (due to their flesh tones), worked wonderfully for the book with few difficulties. Whatever you decide to use for your background, make sure it is smooth and wrinkle-free, non-reflective and not textured. While any color can be keyed out, it is best to use a color that will not be found on your subject(s), be they actor or object.
That brings us to the next part – wardrobe considerations. For obvious reasons, you don’t want your actors wearing a color the same or similar to the background keying color. For example, bright yellow and chroma green are similar enough in color that without perfect lighting this can cause issues.
You need to be careful of white, as it can pick up color spill from the background and result in fuzzy edges on your keyed subjects. And, of course, stay away from clear and reflective objects, such as glasses or a shiny metal sword, as these will also pick up the green of the background and make keying very difficult, though still not impossible (more on this in future blogs).