They have the black and white channels. I upgraded from blender 2.77 to 2.78, and I tried toggling between cycles render and blender render. How do I get the node they are looking at?
The first image is from the material nodes.
The second is from the compositor nodes.
The curve editor in the Compositor works differently, it has additional controls to determine the ranges for the curve.
From the Blender Manual:
Defines the input color that is (linear) mapped to black.
Defines the input color that is (linear) mapped to white