[old_tv_nut]

In the early days, the limited dynamic range of the gamma correction in the camera, combined with some judicious black clipping, combined with the limited contrast of reflective CRT screens, could be and was used to produce the "subject in front of black void" effect. There were some puppet performances on TV (like acts on the Ed Sullivan show) where the puppeteers were in scene but covered in black, and the video engineers just clipped them out of existence.

This became much less possible with the advent of Plumbicon cameras with wide dynamic range including gamma correction down into the shadows. Current solid state cameras for HD and cinema have made the shadows even more clearly visible.

I saw a talk online by a well known cinematographer who said that with film they had figured out the lighting and exposure to give the director either visibility or invisibility in the shadows, but with current digital cinema cameras, they always see into the shadows. They tell the director what he wants to hear, and then achieve the desired effect in post production.

This was illustrated in the live NBC production of Sound of Music, where they had a transition from one location (set) to another by actually dollying the camera through a door with a dark surround; but instead of seeing a black void surround, you could make out details of the studio/set wall.