Silhouette

I have a character with a mat black material. I would like to be able to control the about of light the character reflects. From none, like a cut out silhouette, to a normal amount. Where should I start? Thanks.

Edit: the “Unlit/Texture” works great for the Silhouette, But how would I add light based on a float value from 0 to 1? Thanks.

Not very sure what you want, the most easy way to add light in a pass written by Cg is like this:

Lighting On

float3 color=ShadeVertexLights(v.vertex,v.normal);