Transparency plays a key role in the success of compositing, animation, and interactivity.  By embedding transparency into graphic elements, you can composite different elements together.  This allows for flexibility as it allows elements created at different times to be composited together.

The first image is the original footage.  The second image is the alpha channel generated using a color key.  The third image is the background layer.  The fourth image is the final composite. The embedded alpha channel gives flexibility as it allows different items from the show logo to a video source to be placed behind the hosts during the editing stage.

The Alpha Channel is the technology behind transparency in computer graphics.  It first evolved in the late 1970’s at the New York Institute of Technology and continued to be refined at both Lucasfilm and Pixar. By employing alpha channels embedded into footage layers, transparency data can travel seamlessly between Adobe and Apple Software.  When you color key footage, you can choose to save the footage using a codec that supports embedded alpha channels (such as Animation).