Utilizing green or blue screen (chroma key) in your video projects is a great way to introduce a professional and stylish look to your video productions. Having the ability to change your subject’s background in post production will give you limitless options when it comes to your final product. There are a wide variety of chroma key backgrounds to choose from that will give your video production a polished look similar to larger video productions.
Using a green (or blue) screen in your production pipeline is simple: get a solid green or blue background, film your subject in front of the background, then remove the chroma key in the background using your video editing software and replace it with something else. However, getting a clean key from your footage can be a trial and error process that could cause frustration if the original footage is not shot correctly.
Here are some techniques that you can use to make your green screen background production as seamless as possible:
- Choosing your backdrop
a. Whether you use green or blue (the most common chroma key colors) is up to you. A clean key can be achieved with either color, but you will want to take into account the color of clothing your talent will be wearing and also make sure nothing in your scene closely matches the color of the background color you are trying to remove.
b. Use paint or a drop cloth and try to remove as many wrinkles or variations in the color of your background as you can. The more consistent your background color, the easier time you will have removing it in post production.
- Lighting
a. The most important element of a good green screen video production is the lighting. A well lit scene will allow you to easily tell the software what color to knockout and what elements to keep in the scene.
b. Setup a series of lights that illuminate your backdrop consistently and try to reduce the number of hotspots on the backdrop. Outdoor or fluorescent lighting is a good option because it is a diffused light that spreads evenly across your backdrop.
c. Light your subject well using diffuse lighting as well. Also, a back light that illuminate the back of the subject will help to create a clean edge for your video software to work with.
- Setting up Your Scene
a. Make sure your talent is at least 4 steps in front of your chroma key backdrop. This will help minimize shadows falling onto the green screen and will minimize color spill. Color spill occurs when the reflected green from your backdrop “spills” onto your subject and causes the color of clothing or skin to change hue to match the background. This can cause problems for your color key software and results in rough edges on the final production.
- Video Camera Settings
a. If you have access, try to shoot with the best HD camera possible. A camera that has manual controls for shutter speed, ISO and aperture are best. Set the ISO on your camera to 100 or 200 which should help to reduce signal noise and will smooth out the backdrop in your video.
By following these simple rules and techniques, you should be able to create a clean shot that will allow you to easily remove the chroma key from your background. Now you can replace the green screen with a virtual background or other video background. Have fun!