A quick tutorial on how to use the various outputs from the External Matte node in Davinci Resolve 9.
In a word, the outputs are YRGB & Fill Image, NOT RGBA & Fill Image (as stated in the manual... Sorry, Alexis).
Creating areas of light and shadow are no problem with DaVinci Resolve. PowerWindows, polygons, or curves can be a colorist's best friend when controlling where you want areas of contrast. The only thing that limits you is the simplicity of the shapes.
When shooting on set, a pattern or "gobo" can be placed in front of a light source to create shapes. We can use the same technique in Resolve by using external mattes. In this tutorial I will show how to create more intricate shadows or highlights that can make your images more moody or suggest location.