A green screen is commonly used in video to mask out the background and insert another background instead. For example, instead of flying Arnold Schwarzenegger to Mars in the movie Total Recall (1990), he played in front of a green screen and in post production, the green screen was substituted with “mars”.
This masking technique can also be used in After Effects. I found a video on Envato Elements and inserted her into AE. This is what the original video looked like:
I added the effects Key light, Key Cleaner and Advanced Spill suppressor. In Key Light (1,2) I set the background color to green and tweaked the Screen matte to clip white and black so that the background was completely black and the woman completely white. As in Photoshop and other masking programs, white reveals, black conceals.
Below the video of the photographing woman, I placed an image of Taj Mahal Av Dhirad, CC BY-SA 3.0.
When placing a new background for an object it is important to pay attention to
- The direction of the light source
- The temperature of the light source
- The scale of the object on top
- The frame rate if you put your object on top of another video
- The green screen lightning setup (must be evenly lit)
