Use vertex color as emission color?

I'm looking for help writing a shader that does the following:

1. Takes the current vertex color and inverts it(i.e. white becomes black)
2. Uses that vertex color as the emission color

Any help is appreciated. It seems like it should be a pretty basic thing to accomplish but I can't for the life of me figure it out.

Thanks!

 

For emission to "work" you need a HDR RenderTarget (just tick that checkbox on your camera) and a post processing effect like Bloom (see Image Effects) on your camera.

Inverting a color:
vertColor = 1-vertColor;

Emission:
You need to push the color beyond 1.0f which means you need to specifiy an additional vertex color multiplier to the shader as a property becaus vertex colors are clamped:
vertColor *= _EmissionMultiplier;

Note:
You can multiply black with any number you want. You'll get 0.0f as final output.