In a Merge node, what does the green input represent?

• A. Background node
• B. Foreground node
• C. Alpha channel
• D. Matte input

Answer: (B)

In a Merge node, you’re combining a base image with something on top, and the green input is where the on-top element—the foreground—goes. Connect the image or clip you want to appear over the background to that green port, while the base image sits in the other input (the background). The blue input is typically used for a matte or mask to control where the foreground shows, and the alpha channel is transparency data within the images themselves rather than the port name. So the green input is designated for the foreground.