While struggling to eliminate glare from glasses and refusing to use gimmicks like no lens in the frames, I may have found a near perfect black.
1. Subject is 6 feet from black blackground
2. Windows are heavily draped
3. Subject is seated and all lights point downward
4. Main, Fill, and Hair (Optional) lights are all at least sligtly behind the subject. If you drew a line on the floor 6 feet from the background and parallel to it, you would set your Main and Fill lights on the backgroud side of the line at an anlge of 0 to 30 degrees to the line and pointed at the subject.
5. Now use standard camera setting to discourage the ambient light from being part of
the picture.