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 precisekey from your video 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 troublefree as possible:
- Choosing your backdrop
a. A chroma key background can be any color as long as it is not contained within the foreground elements you would like to keep in the scene. Most video productions utilize either a green or blue screen. 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.
- Illumination
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. Illuminate your subject fully with soft lighting. You may also want to try to add a spotlight pointing at the back of your subject. This will help to cleanly “cut” your subject from the background and will result in a cleaner key.
- Subject Placement
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. Try to shoot your video with the best HD camera you have available. If possible, use a camera that allows you to make manual adjustments to the ISO/Gain, shutter speed and white balance. The ISO/Gain controls should be set to a low setting. This will require more light, but will give you cleaner video with less noise and artifacts.
If you follow these few simple rules, you can create high quality green screen footage that will allow you to easily remove the background in your video editing software.Now you can replace the green screen with a virtual background or other video background. Have fun!
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