Making an object appear completely black until a light source is moved nearby

Hello Unity Community!

I am trying to have an object be completely black (i.e. in complete darkness) until a light source moves near it. Basically I want my light source to be like an orb of light, and I want it to be able to light up other objects when it’s near them, otherwise they remain completely black and indistinguishable from the black background. How do I need to set up my light and the object’s material to achieve this?

Thanks for your time!

Just change the render settings for ambient light to 0.
In Unity 5 this is found under Window > Lighting > Scene

Change your Ambient Source to Color and change color to complete Black