Chroma Key (Green Screen)

What is Chroma Key?

Chroma Key, often called "green screen" or "blue screen," is a visual effects technique for compositing two images or video streams together. It involves removing a specific color from one clip, allowing another clip to show through from a lower track.

This is the technique used in movie special effects to place actors in fantastical environments and by news broadcasters to appear in front of a weather map.

How to Use the Chroma Key Effect

Step 1: Set Up Your Timeline

The key to a successful chroma key effect is layering.

1. Place the background first: Drag the video or image you want to use as your new background onto a lower video track (e.g., Video 1).
2. Place the foreground on top: Drag your green screen (or blue screen) clip onto a higher video track (e.g., Video 2), directly above the background clip.

Step 2: Enable the Chroma Key Effect

1. Select the green screen clip on the top track.
2. In the Effects Panel on the right, open the Effects tab.
3. Find the Chroma Key section and enable the toggle switch.

The default settings are optimized for a standard green screen, so you should see the effect immediately.

Step 3: Fine-Tune the Settings

If your background isn't perfectly removed, you can adjust the following settings:

• Key Color: Click the color swatch to select the exact color you want to remove. Use the eyedropper tool for the most accurate result by clicking on the background color in the main canvas preview.
• Similarity: This slider controls how much "spill" or variation from the key color will be removed. Increase it if parts of the green screen are still visible due to uneven lighting. Decrease it if parts of your subject are becoming transparent.
• Smoothness: This softens the edges of the subject, helping to blend it more naturally with the new background.
• Spill: This helps reduce the color reflection (or "spill") from the green screen onto your subject. For example, if a green light is bouncing off the screen onto your subject's hair, increasing this value can help neutralize that green tint.