If you have negatives that are too foggy for your use, there's always the option of a short bath in Farmer's Reducer.
What you're describing is the result of that black background -- that's what was used in compositing (for movies) as early as 1920 (derived from a still photo double exposure trick), and as late as the original version of Star Wars Episode IV: A New Hope. It was replaced by blue- or green-screen when masking methods were developed that didn't depend on plain old unexposed film. The black, exposed down on Zone 0, records as clear film, at the base+fog level.
I don't have any negatives on hand that look like that; I've got a roll that was a little underexposed (loaded 100 speed in my Debonair, and shot in late-afternoon conditions with some heavy shade) that has pretty deep shadows, but they aren't completely devoid of texture.