A green screen has many uses in a production. Whether it’s for the sake of comedy, instruction, or storytelling, a green screen can increase a project’s production value. However, using one correctly can be tricky. Here are a few helpful tips for lighting and keying out green screen shots.
Lighting the Screen
https://www.youtube.com/watch?v=wD5Z822aT5U
One of the most important steps is lighting your green screen properly. While you obviously need to concentrate on lighting your subjects, unwanted shadows and dark spots on the screen behind them can be difficult to key out in post-production. The perfect key comes from a clean, evenly exposed backdrop.
If you’re in a pinch, a good rule of thumb is to position the subject or actor about 6 to 10 feet in front of the screen. This distance should effectively eliminate any unwanted shadows on the screen while also giving you space outside of the frame to properly set up your lights. However, you can get better results if you take the time to properly calculate this distance beforehand.
Check out the following video for a better understanding of how to balance your chroma and make sense of waveform monitors and color levels.
You can make your life easier by using diffused lights. If you use harsh lights without diffusion, you’ll get an uneven spill. It’s also important to use two of the same type of light so that you can avoid two different fills or temperatures, which would make things very difficult for your editor. However, it’s okay to use two different types of lights for your subject and your screen — provided you light the screen evenly with two of the same type of light. (Side note: be sure to get rid of any distracting or reflective props exposing the green screen before you roll cameras.)
Keying Out the Green
In Adobe Premiere Pro CC, navigate to Video Effects > Keying > Ultra Key. Set the output to “composite,” then you’ll be able to choose your key color, which in this case will be green. After this, you’ll be given a few different options for image control under “Matte Generation.”
After Effect users have a little more wiggle room with their shots. The following tutorial demonstrates the workflow you can expect. As you’ll see, if your green screen isn’t as big as you’d like, you can still capture the image you want. With a little bit of masking, you can isolate the subject and your green screen (or in this case, a loose sheet).
If you’re using a green sheet that allows some background light through, you can fill the area in post-production with the “Screen Matte” tool. This tool allows you too see the grayscale image, which divides the colors into black and white. This way you can eliminate unwanted backdrops by increasing the “Clip Black” property until the transparency is gone.
Working with a green screen can be difficult, but if you know how to plan your shoot with the right software and lighting equipment, the process should go smoothly.
For more info on shooting with and editing green screen footage, check out the following articles.
- How to Chroma Key in After Effects
- The Colorful History of Green Screen Compositing
- Learn How to Properly Use a Green Screen
- The Basic Fundamentals of Lighting a Green Screen
