This page gives some basic details about the Raw Shadow color channel and explains how it is used.
Overview
The Raw Shadow Render Channel stores information about cast shadows calculated from the lighting in the scene. It is a "reverse" image in the sense that white areas indicate shadows while black areas indicate no shadow.
UI Path
||Node Editor|| > Add > Render Channels > Color Channel > Type > Raw Shadow
Common Uses
The Raw Shadows channel is useful for changing the appearance of shadowed areas after rendering in a compositing or image editing application. Below is an example of its use, where the Raw Shadows are added (plus) with the Raw Light pass.
Raw Shadow Render Element
Original Beauty Composite
Shadows lightened by adding the Raw Shadow Render Element
Underlying Compositing Equation
Raw Shadow x Diffuse = Shadow
